Buff
.Buff is a contraction of buffle or buffalo; and buff skin is the skin of the buffalo prepared. “To stand in buff” is to stand without clothing in one’s bare skin. “To strip to the buff” is to strip to the skin. The French for “buff” is buffle, which also means a buffalo.
To stand buff, also written bluff, meaning firm, without flinching. Sheridan, in his School for Scandal, ii. 3, says, “That he should have stood bluff to old bachelor so long, and sink into a husband at last.” It is a nautical term; a “bluff shore” is one with a bold and almost perpendicular front. The word buff, a blow or buffet, may have got confounded with bluff, but without doubt numerous instances of “buff” can be adduced.