denoting an aspect of verbs in some languages, including English, used to express that the action or event described by the verb is or was completed: I lived in London for ten years is perfective; I have lived in London for ten years is imperfective, since the implication is that I still live in London
perfective in American English
(pərˈfɛktɪv)
adjective
1. Rare
tending to bring to or achieve perfection
2. Grammar
designating an aspect of verbs, as in Russian, expressing completion of the action or indicating an action that is not repeated