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]
c. 1300, "kind, sort, class, a class or kind of persons or things sharing certain traits," from Old French gendre, genre "kind, species; character; gender" (12c., Modern French genre), from stem of Latin genus (genitive generis) "race, stock, family; kind, rank, order; species," also "(male or female) sex," from PIE root *gene- "give birth, beget," with derivatives referring to procreation and familial and tribal groups.
Also used in Latin to translate Aristotle's Greek grammatical term genos. The grammatical sense is attested in English from late 14c. The unetymological -d- is a phonetic accretion in Old French (compare sound (n.1)).
The "male-or-female sex" sense is attested in English from early 15c. As sex (n.) took on erotic qualities in 20c., gender came to be the usual English word for "sex of a human being," in which use it was at first regarded as colloquial or humorous. Later often in feminist writing with reference to social attributes as much as biological qualities; this sense first attested 1963. Gender-bender is from 1977, popularized from 1980, with reference to pop star David Bowie.
mid-14c., "belonging to the male grammatical gender;" late 14c., "of men, of male sex," from Old French masculin "of the male sex" (12c.), from Latin masculinus "male, of masculine gender," from masculus "male, masculine; worthy of a man," diminutive of mas (genitive maris) "male person, male," a word of unknown origin. The diminutive form might be by pairing association with femininus (see feminine). Meaning "having the appropriate qualities of the male sex, physically or mentally: Manly, virile, powerful" is attested by 1620s. As a noun, "masculine gender," from c. 1500.