Infinitives

What Does the Infinitive Form Mean?

The infinitive form is the most basic form of a verb. It doesn’t have a tense, and it isn’t tied to any one subject in a sentence.

In the sentence He is going to go to the shop., “to go” is the infinitive. You can normally spot an infinitive because it has to at the start (though sometimes they don’t—more on that later).

If we change who is going to the shop, like this:

• She is going to go to the shop.
• They are going to go to the shop.

you can see that the infinitive, to go, doesn’t change.

It’s the same with tense. Whether you’re writing in the past, present, or future tense, the infinitive stays the same.

Past: They wanted to go to the theatre.

Present: Do you want to go to the theatre?

Future: I am going to go to the theatre next Saturday.

This is because the infinitive is never the main verb in the sentence. In the examples above, the main verb phrases are “they wanted,” “you want,” “I am going.”

As you can see, those phrases do change according to the tense and the subject. This is a good way to tell the difference between normal verbs and infinitives.

How Do You Write the Infinitive Form?

In the infinitive form, “to” is a part of the verb. To write the infinitive form, you’ll normally need this formula:

“to” + verb

(Again, sometimes you can get rid of the “to,” but we’ll look at that later.)

What Is a Verb?

Need a quick refresher on verbs? No problem. A verb is a doing word. They denote an action or a state of being. Here are some verb examples:

• Hear
• See
• Be
• Do
• Walk
• Wear
• Call
• Write

It’s important to note that some of these words aren’t always verbs in every sentence—some can also be used as nouns. Check out our complete guide to verbs for more info.

Examples of Infinitive Forms

So, how do you turn those verbs into infinitives? Just add “to.”

Here are 15 more examples of the infinitive form to help you learn how it works:

• To be: I want to be the leader.
• To do: I don’t know what to do.
• To see: He went to see the doctor.
• To hear: I have some news you might not want to hear.
• To learn: She is trying to learn Spanish.
• To take: I am going to take a vacation.
• To have: They would like to have dinner with you.
• To sleep: Did you manage to sleep well?
• To care: I stayed there to care for her while she was sick.
• To eat: Have you had enough to eat?
• To promise: She wanted me to promise not to do it again.
• To wear: I have nothing to wear.
• To want: That is a strange thing to want.
• To dance: Would you like to dance with me?
• To read: She loves to read thriller novels.

As you can see, the infinitive stays the same regardless of tense or sentence subject.

The Full Infinitive and the Bare Infinitive

Most of the time, you won’t need to be able to name the exact type of infinitive you’re using, and the definition above will be enough to get you through.

But just in case you need to know what the full infinitive and the bare infinitive are, we’ve got you covered.

So far, we have been looking at the full infinitive. The full infinitive is any infinitive with “to” at the start (to eat, to dream, to dance, etc.).

You may have also heard of the bare infinitive. All this means is that we take away the “to” (eat, dream, dance).

How Does the Bare Infinitive Work in a Sentence?

She could play the piano beautifully.

In this sentence, the bare infinitive is “play.” It is called the bare infinitive because there is no “to” before it.

It would be wrong to write She could to play the piano beautifully.

If you’re unsure whether to use “to” with an infinitive, check with ProWritingAid. It’ll highlight when you’ve used an infinitive incorrectly and show you how to fix it:

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Here are some examples of bare infinitives in a sentence. They’re in bold to help you spot them.

• Mom made me bring my sister.
• I’d rather be on my own.
• You had better take a coat with you.
• He should know better than that.
• I heard them sing at a festival.
• You must get up for school.
• Why wait until next year?

Can I Use an Infinitive as a Noun, Adjective, or Adverb?

What a specific question! Yes, you can use an infinitive as a noun, adjective, or an adverb. In each case, the infinitive will play a different role in the sentence:

• Noun: a word that denotes a thing, place, person, or idea
• Adjective: a word that describes a noun
• Adverb: a word that modifies (changes the meaning of) a verb

What Are Examples of an Infinitive Used as a Noun?

When you use an infinitive as a noun, you use it to denote an idea or thing, like this:

• I want to know.

To know stands in for the thing that I want in this sentence (knowledge). This infinitive therefore acts as a noun.

Here are some more examples:

• After a long day, Janelle likes to soak in a hot bath.
• I love to dance.
• She refuses to cater to his every whim.
• I need to learn my words.
• To visit the Grand Canyon is his life-long dream.
• To know him to to love him.

As in the examples above, the noun infinitive phrase can go at the end or the beginning of the sentence, though it’s more common to see it at the end.

How Do I Use the Infinitive as an Adjective?

An adjective describes a noun. So when you use an infinitive to describe a noun, you’re using it as an adjective.

• Jennifer’s first attempt to win the gold medal failed.

Here, the noun is “attempt.” The phrase “to win the gold medal” describes the noun—the “attempt.”

• He used computer software to build the game.
• She wore her mom’s necklace to give her good luck.
• I am happy to be here.
• It is good of you to think of me.
• The puppy is naughty to destroy the sofa.

What Are Examples of the Infinitive Used as an Adverb?

When you use the infinitive to modify (or change the meaning of) a verb, you’re using it as an adverb.

• She ran to catch the bus in time.
• He sent a letter to make a complaint.
• They were studying to prepare for the exam.
• To keep you safe, we’re continuing to wear face coverings.
• Jessica went to New York to study acting.

As you can see, the infinitive phrase can go at the beginning or end of the sentence:

• To keep you safe, we’re continuing to wear face coverings.
• We’re continuing to wear face coverings to keep you safe.

What Does the Infinitive Phrase Mean?

You’ve already seen some infinitive phrases in the examples above.

Here are three of those examples with the infinitive phrases highlighted:

• After a long day, Janelle likes to soak in a hot bath.
• They were studying to prepare for the exam.
• She wore her mom’s necklace to give her good luck.

As we’ve said, an infinitive phrase can go at the beginning or end of the sentence, but the end is more common. A famous exception is the line “To be or not to be, that is the question” from Hamlet.

You can use infinitives to make lots of different kinds of statements. Let’s look at a few.

To Explain a Description of Something

Infinitives are used after an adjective to expand an idea. For example:

• The puppy is naughty to destroy the sofa.

Here, we are told not only that the puppy is naughty (adjective) but that it was the action of destroying the sofa that made him naughty. The infinitive to destroy expands on the adjective, naughty.

Examples of infinitives being used to explain adjectives:

• It is good of you to think of me.
• I am happy to be here.
• It is important for students to be patient in the laboratory.

To Explain Why You Like/Dislike Something

If you use an infinitive with the words “too” or “enough,” you can express the reasoning behind satisfaction or dissatisfaction.

• There’s too much sugar to fit in this bowl.

The bowl is no good because it isn’t big enough to fit all the sugar.

• I had too many books to carry.
• This soup is too hot to eat.
• Jeff was too tired to work.
• He arrived too late to hear the opening chorus.
• I’ve had enough food to eat.
• She’s old enough to decide for herself.
• There isn’t enough snow to ski down the slope.

To Make a Comment or Judgment About Something

Use infinitives to make a comment or judgment about a noun in a sentence.

For example:

• Climbing the beach cliff is a dangerous way to behave.

Here, the infinitive tells us that the judgement is being made specifically about behaviour.

More examples of making a judgement with an infinitive:

• Your comment was a rude thing to say.
• This is the right thing to do.
• Those were the wrong formulas to use.
• Jack is the best candidate to hire.

To Ask a Question

The verbs ask, decide, explain, forget, know, show, tell, and understand can be followed by a question word such as where, how, what, who, and when + the infinitive to form a question.

It’s easier when you see some examples:

• She asked me how to use the new computer.
• Do you understand what to do?
• Tell me when to press the button.
• I’m not sure I know who to call.

Now you know what the infinitive form is, you can begin to add infinitive phrases to your sentences.

See what we did there?

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Ok, let’s face the facts: English is a tough and often weird language. English grammar is rarely cut and dry. We all know it, so why mention this now? Well, we’re about to talk about infinitives. Are they verbs? Are they nouns? Are they adjectives? Are they adverbs? Are they taking all of our missing socks? The answer to the last question is “No” (probably), but the other questions are trickier to answer. Many parts of speech don’t like staying in their own little area and will sometimes cross over into other categories. Infinitives are a perfect example of English complexity, so let’s try as best we can to nail down these tricky words—after we double check our sock drawer.

What is an infinitive?

Things are going to get a little complicated so let’s start simply. An infinitive is a verb form that can be found in many languages, and each of them uses infinitives differently. For example, if you have ever studied Spanish, you know that words like hablar (“to speak”), gustar (“to like”), and leer (“to read”) are infinitives. In English, an infinitive is identical to the simple or basic form of the verb you will find if you look one up in our dictionary. Eat, sleep, play, and go are examples of infinitives. As you might know, the first person singular present tense also typically resembles the base form of the verb, as in the sentence I sleep.

So, how do we actually use infinitives? Well, infinitives are not often used by themselves. In most sentences, an infinitive will follow a modal verb in a verb phrase as in can leave or must buy or it will follow a function word, almost always to, as in the famous “To be or not to be” from Shakespeare’s Hamlet. When an infinitive is used with a function word and other words, we refer to this as an infinitive phrase. This can be confusing, as many English speakers will also refer to infinitive phrases such as to run or to move as simply “infinitives.”

Infinitives are derived from verbs and can act as verbs when used with an auxiliary verb (helping verb) in a sentence. For example, the following sentences use infinitives with modal verbs:

 

• I can play three different instruments.
• You must give me the money you owe me.
• My sisters and I would watch cartoons every Saturday when we were kids.

Is this the only way we can use infinitives? Not by a long shot! Let’s look at the different types of infinitives to see how useful they can be.

Get some help learning more about auxiliary verbs in this closer look at them.

Types of infinitives

Infinitives and infinitive phrases come in several different types, and they all have their specific uses in sentences.

Nominal infinitives 

In grammar, the word nominal means that something can function as a noun in a sentence. Like gerunds, infinitive phrases can function as a noun in a sentence or clause. This means that infinitive phrases can be subjects, direct objects, or objects of prepositions. For example:

 

• Subject: To play professional baseball is my son’s dream.
• Direct object: All of my friends want to go to the concert. 
• Object of a preposition: We had no choice but to obey.  

Adverbial infinitives

The word adverbial means that something can function as an adverb. Adverbs modify verbs, adjectives, and clauses. So, adverbial infinitive phrases can also be used to modify these things. For example:

 

• She agreed to negotiate. (Modifies the verb agreed)
• The movie was too quiet to hear. (Modifies the adjective quiet)
• To find change on the beach, you will need a metal detector. (Modifies the main clause)

Adjectival infinitives

As you might guess, the word adjectival means something can function as an adjective. Adjectives modify nouns and pronouns, so adjectival infinitive phrases are—you guessed it!—used to modify nouns and pronouns:

 

• When it comes to romance, Juan is the guy to ask. (To ask modifies the noun guy)
• It is for me to know and for you to find out. (To know modifies the pronoun me and to find out modifies the pronoun you)

Bare infinitives 

Sometimes, the word to is omitted from an infinitive phrase. When it is, we refer to this as a bare infinitive. Often, bare infinitives make a sentence look less awkward than if the word to was present:

 

• Captain Hook made Peter Pan walk the plank.
• Our mean teacher let us sweat a little before reading the exam results.
• Everyone wanted to hear her sing songs from her new album.

Infinitives in the passive voice 

It is possible to put infinitives in the passive voice. When we use the passive voice, the subject has something happen to it rather than perform an action itself. To use an infinitive in the passive voice, we use the verb be followed by a past participle of a verb. For example:

 

• There is work to be done. 
• The fish need to be fed and the cats have to be let out.

Infinitives in the present perfect tense

It is possible to use an infinitive phrase in the present perfect tense. To do so, we use the verb have with the past participle of a verb:

 

• It would have been nice to have talked to Ashley before she left for college.
• Based on the fossil record, it would’ve been impossible for cavemen to have ridden dinosaurs.

Dip into all the present tenses, including the present perfect, with this article.

What are split infinitives? Rules and best practices

Although it may frustrate your English teacher, it is possible to split up an infinitive with the word to in an infinitive phrase in order to put a modifier in between. We refer to these split infinitives as … split infinitives. A famous example of this is found in the opening of Star Trek, which states the crew has a mission “to boldly go where no man has gone before.” In most cases, the modifier that splits the infinitive is an adverb. Because many sentences would sound awkward if the adverb followed the entire infinitive phrase, we often split an infinitive to make a more natural sounding sentence. You can see this in the following two sentences:

 

• Henry tried and failed to walk his big clumsy dog Rufus slowly down the street.
• Henry tried and failed to slowly walk his big clumsy dog Rufus down the street.

Both of these sentences are grammatically correct and have the same meaning, but the second sentence splits the infinitive to move the adverb toward the beginning of the sentence. As a result, the second sentence is a little easier to read and understand.

You can learn more about split infinitives in our more detailed exploration of them.

Infinitives vs. prepositional phrases

In many sentences, an infinitive is accompanied by the word to. If you see the word to followed by the base form of a verb, you are almost always dealing with an infinitive phrase.

However, not every phrase that begins with to is an infinitive phrase. To is also a commonly used preposition, which means it can also be used to begin prepositional phrases. When used in a prepositional phrase, to is followed by a noun, pronoun, noun phrase, a word acting as a noun, and any other modifiers. You’ll notice that a preposition phrase doesn’t include a verb or word acting as a verb, which is the key to differentiating it from an infinitive phrase. The following sentences show this difference between infinitive phrases and prepositional phrases:

 

• Infinitive phrase: It is time to eat lunch. (To is followed by an infinitive, not a noun)
• Prepositional phrase: Bring my lunch to me. (To is followed by a pronoun)

However, there are two things you should watch out for:

1. When used as a preposition, to can be followed by a gerund. A gerund looks like a verb, but it is used as a noun. Gerunds also always end in -ing, which infinitives never do.

 

• They resorted to burning furniture for warmth. (Burning is a gerund that begins a gerund phrase)

2. It is possible for long prepositional phrases to have infinitive phrases within them.

 

• She gave the letter to the man who knew how to dance the fandango. 

In the sentence above, the verb gave is modified by a long prepositional phrase that begins with to the man and has an infinitive phrase within it. Remember, infinitive phrases can modify nouns, adjectives, and adverbs. But wait, there’s more! A noun within an infinitive phrase can also be modified by a preposition phrase, too. This can possibly lead to extraordinary long (and silly) sentences involving many subordinate prepositional phrases that modify nouns within infinitive phrases:

 

• I brought the package to the woman who asked to use the bathroom to the left of the table of the chef that learned to make desserts by watching fancy cooks who went to French culinary schools to learn their trade.

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