mid-14c., "perseverance, a keeping up, a going on," from Old French continuance (13c.), from continuer (see continue). From late 14c. as "a holding on or remaining in a particular state;" in law, "the deferring of a trial or hearing to a future date" (early 15c.).
"practice or hobby of dressing as a character from a movie, book, or video game, especially one from Japanese manga and anime," 1993, according to Merriam-Webster, from costume (n.) + play (n.), based on a Japanese word formed from the same English elements and alleged to date from 1983. Also used as a verb.
early 19c. U.S. colloquial, "a female, a woman," from she + male.
Davy Crockett's hand would be sure to shake if his iron was pointed within a hundred miles of a shemale. ["Treasury of American Folklore"]
This became obsolete, and by 1972 it had been recoined (disparagingly) for "masculine lesbian." The sense of "transsexual male" seems to date from c. 1984.