C14: from Latin effēmināre to make into a woman, from fēmina woman
Word Origin and History for effeminate
adj.
early 15c., from Latin effeminatus "womanish, effeminate," past participle of effeminare "make a woman of," from ex- "out" (see ex-) + femina "woman" (see feminine). Rarely used without reproach. Related: Effeminately.