late 14c., from Old French insufficient (14c.) or directly from Late Latin insufficientem (nominative insufficiens) "not sufficient," from in- "not, opposite of" (see in- (1)) + sufficientem (see sufficient). Originally of persons, "inadequate, unable;" of things, "lacking in what is necessary or required," from late 15c. Related: Insufficiently.
updated on December 13, 2015