1. quality of being imperfect, faultiness; flaw, defect, shortcoming. imperfectionim`per*fection , n. [l. imperfectio: cf. f. imperfection. see: imperfect, a.] the quality or condition of being imperfect; want of perfection; incompleteness; deficiency; fault or blemish. sent to my account with all my imperfections on my head