boudoir n.

"thrust out the lips, as in sullenness or displeasure," mid-14c., of uncertain origin, perhaps from Scandinavian (compare Swedish dialectal puta "to be puffed out"), or Frisian (compare East Frisian püt "bag, swelling," Low German puddig "swollen"); related via notion of "inflation" to Old English ælepute "fish with inflated parts," Modern English pout as a fish name, and Middle Dutch puyt, Flemish puut "frog," all from a hypothetical PIE imitative root *beu- suggesting "swelling" (see bull (n.2)). Also compare French bouder "to pout," also presumably imitative (and the source of boudoir). Related: Pouted; pouting.

As a noun from 1590s; "a protrusion of the lips as in pouting; a fit of sullenness or displeasure."

1869, in dressmaking, "puffed out, bulging," from French bouffant, present participle of bouffer "to puff out," from Old French bouffer (12c.), from Vulgar Latin *buffare, probably ultimately imitative of puffing. As a noun by 1870. Earlier as a French word in English. Used of hairdo styles from 1955.

"quietly sullen," 1744, of uncertain origin. Connection has been suggested to obsolete, rare sulke "hard to sell" (1630s) and to Old English asolcen "idle, lazy, slow," past-participle adjective from aseolcan "become sluggish, be weak or idle" (related to besylcan "be languid"), from Proto-Germanic *seklan (source also of Middle High German selken "to drop, fall"). But words of similar meaning often are held to be imitative (compare miff, mope, boudoir). Related: Sulkily; sulkiness.