E. Cobham Brewer 18101897. Dictionary of Phrase and Fable. 1898.
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 ones 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.
And for the good old cause stood buff,
Gainst many a bitter kick and cuff.
Butler: Hudibrass Epilaph.
I must even stand buff and outface him.Fielding.
BUFF in Blind-mans buff, the well-known game, is an allusion to the three buffs or pats which the blind-man gets when he has caught a player. (Norman-French, buffe, a blow; Welsh, paff, verb, paffio, to thump; our buffet is a little slap.)