An infinitive is the base form of a verb that can function as a noun, adjective, or adverb. As a noun, an infinitive can be the subject or direct object of a sentence. As an adjective, an infinitive can modify or describe a noun. As an adverb, an infinitive can provide more information about verbs, adjectives, or other adverbs in a sentence. Examples are provided for infinitives functioning in each part of speech.