a tense of verbs used in describing action that is on-going
"She was imperfectly explaining her theory when I walked into the room, so she started over from the beginning."
something having a minor flaw
"The vintage watch keeps good time despite its imperfect crystal, which has a tiny chip in the corner."
to make imperfect
"The constant rain made the once-pristine garden path look imperfect."
not perfect; defective or inadequate
"had only an imperfect understanding of his responsibilities"
"imperfect mortals"
"drainage here is imperfect"
not perfect
"The vintage painting was truly imperfect because a few brushstrokes were missing, but it still held great charm."
The word comes from the Latin imperfectus, meaning "not finished." It entered English via Middle English and Old French, where it originally described something that was incomplete or unfinished.