c. 1600, "sameness, oneness, state of being the same," from French identité (14c.), from Medieval Latin identitatem (nominative identitas) "sameness," ultimately from Latin idem (neuter) "the same" (see idem). [For discussion of Latin formation, see entry in OED.] Earlier form of the word in English was idemptitie (1560s), from Medieval Latin idemptitas. Term identity crisis first recorded 1954. Identity theft attested from 1995. Identity politics is attested by 1987.
"[I]dentity politics" [is] a phrase with notably wide currency in gay and lesbian communities. In common usage, the term identity politics refers to the tendency to base one's politics on a sense of personal identity—as gay, as Jewish, as Black, as female ..... [Diana Fuss, "Essentially Speaking," 1989]
early 15c., occultacioun, "disguise or concealment of identity," from Latin occultationem (nominative occultatio), noun of action from past-participle stem of occultare "to hide, conceal," frequentative of occulere "to cover over, conceal" (see occult).
computerese word, 1948, coined by U.S. computer pioneer John W. Tukey, an abbreviation of binary digit, probably chosen for its identity with bit (n.1).