privative (adj.)

late 14c., privatif, "characterized by absence of a quality, characterized by taking away or removal of something," from Latin privativus "denoting privation," in grammar, "negative," from privatus, past participle of privare "to deprive, rob, strip" of anything; "to deliver from" anything" (see private (adj.)).

In grammar, from 1580s as "expressing negation, changing the sense of a word from positive to negative" (as do the prefixes un-, an- (1), in- (1), a- (3), etc.). Related: Privatively.