Gaff

Definition and stakes

Albert Barrère,  Argot and Slang

“ Gaffe, m. and f. (thieves’) , sentry; thief on the watch, or “crow;” prison warder, or “bloke.”
Les gaffes (gardiens) ont la vie dure. Ils tiennent sur leurs pattes comme des chats ... si je l’ai manqué, je ne me suis pas manqué, moi, je suis sûr d’aller à la butte.—Mémoires de Monsieur Claude.
Gaffe à gail, mounted police; —— de sorgue, night watchman; —— des machabées, cemetery watchman. Etre en ——, faire ——, to be on the watch, “to dick.”
Riboulet et moi, nous étions restés en gaffe afin de donner l’éveil en cas d’alerte.—Vidocq.
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Source: Gutenberg

John S. Farmer,  Slang and its analogues past and present…

“ Jon Bee, Living Picture of London, p. 241. If the person calling for ‘man’ or ‘woman’ is not right or wrong at five guesses, neither of the gaffers win or lose, but go again.
Verb. (venery) .—To copulate. For synonyms, see Greens and Ride.
Gaffing, subs. (old) .—See quot.
1821. Pierce Egan, Life in London, p. 279. Gaffing was unfortunately for him introduced. Ibid. Note.—A mode of tossing for drinks, etc., in which three coins are placed in a hat, shaken up, and then thrown on the table. If the party to ‘call’ calls ‘heads’ (or ‘tails’) and all three coins are as he calls them, he wins
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Source: Gutenberg

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