insufficient (adj.)youdaoicibaDictYouDict[insufficient 词源字典]
late 14c., from Old French insufficient (14c.), from Latin insufficientem (nominative insufficiens) "insufficient," from in- "not, opposite of" (see in- (1)) + sufficientem (see sufficient). Originally of persons, "inadequate, unable;" of things, from late 15c. Related: Insufficiently.[insufficient etymology, insufficient origin, 英语词源]