perfectiveaspect

Perfective aspect is a grammatical category that marks an action as complete, bounded, and viewed as a whole rather than as ongoing or repetitive. It foregrounds the endpoint or result of the event. By contrast, the imperfective aspect presents actions in progress, habitual, repeated, or without focusing on termination.

In many languages, perfective and imperfective are expressed as a pair of forms. In Slavic languages such as Russian, Polish, and Czech, the distinction is morphologically productive, often via prefixes or different verb stems. For example, Russian читaть (imperfective) versus прочитать (perfective) shows how a single lexical meaning can be realized in two aspectual modalities. The imperfective form encodes ongoing processes or repeated actions, while the perfective form denotes a single completed act or a result. In the future tense, perfective forms typically signal a completed action, whereas imperfective forms can express ongoing or habitual future activities.

In English and some other languages, the perfective is not a separate verb category but is conveyed through tense and aspectual constructions such as the perfect and progressive. Present perfect, as in "I have finished," emphasizes result or relevance to the present; past progressive, as in "I was reading," marks ongoing activity in the past. Some languages use aspectual prefixes, particles, or auxiliary constructions to build the perfective meaning without a distinct grammatical class.

Cross-linguistically, the boundary between perfective and imperfective interacts with tense, mood, and telicity. Many languages allow combinations that encode aspect with time reference, yielding nuanced distinctions about completion, duration, repetition, or punctuality.