I. (ˈ)im, əm+ adjective
Etymology: alteration (influenced by Latin imperfectus ) of Middle English imperfit, imparfit, from Middle French imparfait, from Latin imperfectus, from in- in- (I) + perfectus perfect — more at perfect
1.
a. : falling short of perfection : not perfect (as in form, development, or function) : not complete in parts or attributes : not satisfying the standard or ideal : defective , inadequate , incomplete
had only an imperfect understanding of his task
in the imperfect light of the moon — Anthony Trollope
what an imperfect husband he had always been — H.G.Wells
imperfect mortals
drainage of the region is imperfect — Journal of Geology
b. : diclinous
2. : of, relating to, or being a verb tense used to designate a continuing state or an incomplete action especially in the past
3.
a. in medieval church music
(1) : twofold rather than threefold in time value — used of notation; compare perfect
(2) : having a duple rather than triple rhythm — used of a rhythmic mode
b. : diminished 2
4. : not enforceable at law : lacking some essential element required by law : depending for fulfillment upon moral rather than legal duty
an imperfect obligation
: enforceable only under certain conditions : defeasible
an imperfect mortgage
an imperfect grant avoidable by the government
• im·perfectly “+ adverb
• im·perfectness “+ noun -es
II. transitive verb
obsolete : to make imperfect
III. (ˈ)im, əm+ noun
: an imperfect tense ; also : the verb form expressing it