Word Origin & History
early 14c., from O.Fr. desguisier, from des- "away, off" + guise "style, appearance." Originally primarily "to put out of one's usual manner" (of dress, etc.); noun meaning "a garb assumed in order to deceive" is first recorded 14c. Original sense preserved in phrase disguised with liquor (1560s).
"It is most absurdly said, in popular language, of any man, that he is disguised in liquor; for, on the contrary, most men are disguised by sobriety." [Thomas de Quincy, "Confessions of an English Opium-Eater," 1856]