Nonfinite

Nonfinite refers to verb forms and clauses that do not express finiteness. Finite verbs carry tense, person, number, and mood; nonfinite forms lack these properties and cannot serve as the main predicate of an independent clause. In many languages, nonfinite forms occur in subordinate clauses, in noun phrases, or as modifiers, and they often participate in complex periphrastic constructions. The main nonfinite forms in English are infinitives, participles, and gerunds.

Infinitives include to go or bare infinitives after certain verbs: I want to go; Go is useful in command formats or after modals. Infinitive clauses can also function as subjects: To travel broadens the mind. Participles come in present and past varieties. Present participles (going, running) are used for progressive aspect or as modifiers: the running water. Past participles (gone, broken) can function as adjectives or form passive or perfect constructions: a broken window, the door was opened. Gerunds are -ing forms that function as nouns: Swimming is fun; They enjoy swimming. Some languages differentiate between infinitive, participial, and gerund forms more clearly than English, while others merge these functions differently.

Nonfinite clauses serve various roles. They can act as complements to verbs (I want to leave), as subjects or objects (Leaving early is risky; To err is human), or as modifiers (the man standing there). They can participate in aspectual or temporal constructions with auxiliary verbs (having finished, going to win). Cross-linguistically, nonfinite forms vary in availability and usage, reflecting differences in how languages encode verb semantics like aspect, modality, and clause linkage without relying on a finite main verb.