Green’s Dictionary of Slang

1. one who looks over a card-player’s shoulder, advising and interfering with the game.

1922		T.A. Dorgan in Zwilling TAD Lex. (1993) 51: Trying to play pinochle with a flock of kibitzers standing behind your chair.
1931		Dundee Courier 21 Dec. 6/4: We’ve got [...] a butler who is a discreet ‘kibitzer.’ I always insist that our butler be a bridge player himself.
1934		B. Appel Brain Guy (1937) 44: The bulldog had changed into a kibbitzer at a card game.
1938		A.J. Liebling Back Where I Came From (1990) 279: I couldn’t sell out the kibitzers, that had bet on me up to $500.
1948		Courier (Waterloo, IA) 26 Feb. 17/3: There are many varieties of kibitzers, including the button-holer, the elbow-nudger, and the guy who plays a paradiddle on your collar bone.
1952		J. Jones From Here to Eternity (1998) 333: Stark, some kibitzer whispered, had in the last hour dropped the whole $600 he had managed to build up since ten o’clock.
1968		T. Thackrey Gambling Secrets of Nick The Greek 27: He gave sundry other gentlemen by courtesy (who had entered the scene as side-betting kibitzers) his promissory note for $560,000.
1981		E. Bunker Little Boy Blue (1995) 55: One group in a corner was playing Monopoly, complete with kibitzers.
1990		J. Healy Streets Above Us (1991) 93: Mo joins the ranks of kibitzers. ‘When you don’t know what to do, wait for your opponent to make the play.’.
2002		J. Franzen Corrections 298: The Strindberg Room was packed with kibitzers, low-stakes blackjack players, and lovers of the slot.

2. anyone who butts in or meddles, offering usu. unwanted advice.

1922		L.A. Times 4 May sect. II 4: Herewith another installment of snappy younger generation slang just broadcast from eastern points, where it has its origin: Kabitzer: A fellow who stands around a dance hall or card game giving unasked-for advice; a noisy wall flower.
1926		Judge (NY) 91 July-Dec. 31: Kibetzer - A wise guy; a spoofer.
1930		Nottingham Eve. Post 12 Sept. 3/3: The American-Hebrew expression [...] ‘the kibitzer’ is that of a delightful person who loves to interfere in his friends’ business.
1930		W. Winchell On Broadway Feb. 1 [synd. col.] Many of the letter writers [...] acted in the kibitzer manner [...] winding up their missive along sentimental lines.
1946		P. Bowman Beach Red 88: Sightseers, souvenir hunters and general kibbitzers.
1947		B. Schulberg Harder They Fall (1971) 87: The non-belligerent echelons, the managers, trainers, match-makers, gamblers, minor mobsters, kibitzers.
1965		W.C. Anderson Adam M-1 135: She wanted the demonstration [...] where we could be alone and not heckled by a bunch of drunken kibitzers.
1977		D. Powis Signs of Crime 190: Kibbitzer Generally, one who interferes or gives unwanted advice in an annoying fashion, but especially as an onlooker at a gambling situation, usually a card game (common Yiddish East End expression).
1989		H. Rawson Dict. of Invective (1991) 225: The intruder who does all these nasty things is, naturally, a kibitzer, i.e., a buttinkski.

3. one who seeks something for nothing.

1927

W. Winchell Your Broadway & Mine 15 June [synd. col.] A polite but firm warning which told visiting kibitzers that the free list had been suspended and only newspaper men and critics were privileged to frequent the Palace Theatre sans paying.