Infinitive Verbs Explained: 5 Functions of Infinitive Verbs

An infinitive verb is the basic form of a verb in the English language. Infinitive verbs are non-finite verbs, meaning they can take on the form of other parts of speech. They’re often preceded by the word “to,” as in “to run.”

As a non-finite verb, an infinitive verb is never the main verb of a sentence or independent clause. Other non-finite verbs include gerunds and present participles, which both conjugate verbs with the “-ing” form. In contrast, the infinitive form of a verb is never conjugated.

There are three general types of infinitive verbs:

1. 1. Bare infinitives: A bare infinitive is the base form of a verb without the presence of the word “to” preceding it. A bare infinitive typically follows modal verbs like “can” and “will” as well as any of their conjugations like “could” or “would.” Bare infinitives can also follow common verbs such as “make” and “let.”
2. 2. Full infinitives: A full infinitive includes the word “to” before a bare infinitive. In this context, the word “to” does not act as a preposition. Instead, it forms an infinitive phrase rather than a prepositional phrase. Full infinitives are the most common form of infinitive verbs and they often express motivation for action.
3. 3. Split infinitives: Split infinitives include an adverb between the word “to” and the bare infinitive to enhance and modify the infinitive phrase. Split infinitives are rarely used in formal writing.

To learn more about how to properly use infinitive verbs, consider their five main functions:

1. 1. Direct object: One of the most common uses of infinitive verbs is as the direct object of the verb. It can act as the noun or noun phrase that receives the action of the verb.
2. 2. Subject: Another common use of infinitive verbs is as the subject of a sentence. In this context, the infinitive verb acts as the action driving the sentence.
3. 3. Subject complement: If infinitive verbs follow a linking verb, they act as complements to the subject of the sentence.
4. 4. Adjective: Infinitive verbs can act as a modifier to the noun of a sentence and thus take on the role of an adjective.
5. 5. Adverb: An infinitive verb can modify the main verb of a sentence by serving as an adverb.

Explore some of the following sentences as examples of how infinitive verbs are used in English grammar:

1. 1. “We want to hike.” “To hike” is the full infinitive in this sentence. It is used as a direct object that receives the action of the verb “want.”
2. 2. “Mom asked you to quickly clean your room.” This split infinitive includes the adverb “quickly” to break up the full infinitive “to clean.”
3. 3. “Let him speak.” In this example, “speak” is the bare infinitive following the verb “let.”
4. 4. “My dream is to travel more.” In this example, “to travel” is the full infinitive used as a subject complement to the subject “dream.” This full infinitive is connected by the linking verb “is.”
5. 5. “I go to the library to read.” The full infinitive “to read” is used as an adverb to modify the main verb “go” and clarify the motivation for why the subject is performing the action.

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