Meaning an onlooker at a game of cards, this is the OED’s etymology:

Yiddish, < German kiebitzen to look on at cards, < kiebitz lapwing, pewit; interfering onlooker at cards.

What has a lapwing got to do with cards?

A kibitzer (in its most extreme form) is not just a passive bystander; he/she peers over players’ shoulders, breathes heavily on them*, makes intrusive comments, and is generally a distracting nuisance. The association with the lapwing may have to do with that bird’s practice of distracting predators away from its nest (by hopping about pretending to be injured); or to the bird’s courtship display, which is said to be particularly hectic and noisy. See Wikipedia, s.v. Northern Lapwing. Of course, I might be quite wrong (wouldn’t be the first time, nor yet the last), and there’s some simpler, more elegant explanation.

I’ve known for a long time what a kibitzer is, but this is the first I’ve heard about any association with a lapwing. Thank you, ElizaD.

*In some parts of Europe, this could entail a powerful - and not always welcome - afflatus of garlic, spirituous liquors, stale tobacco, carious teeth, etc.

And thank you, lionello.  I’m guilty of all of those things, particularly the intrusive comments bit.  Do we have many card players here?

In our high school chess club (a long time ago) this term was used for onlookers in a chess game who would suggest moves to the players and otherwise interfere with the play.

That, I think, is the classic use.

Time back way back during my first trial run through college the whist players had a hierarchy of onlookers. Of the ones I remember kibitzer was the lowest.  Kibitzers could watch but not make any audible comments.  Next level up was the tzitzers; they could go “Tsk, tsk” went they thought someone wasn’t making the best move.  The top level was the dorbitzers.  They were allowed to actually make coherent comments.  This usage was extremely local and should not be taken as a blanket statement about these words.

Haven’t heard any of the others in relation to bridge.  There’s so much etiquette that I doubt anyone would dare to interfere.

I play neither whist nor bridge, so can’t comment based on personal experience. Googling provides lots of info. on these, to me, strange characters. Here’s one site: http://news.google.com/newspapers?nid=1350&dat=19601211&id=WggwAAAAIBAJ&sjid=AwEEAAAAIBAJ&pg=4602,4303253

Wow!  I thought those terms had just been invented by my friend.  Now I don’t know if they were and somehow made it into the great outside world or whether he got them from real life and whether I have misremembered the order or whether they got shuffled somewhere in the course of moving about.

The world is indeed full of a great number of things.

Edit:  Addenda

I see by the date of this article that it was before I learned the terms from my friend.  That would have been between September 1961 and June 1964.

Just for completeness: Kibitz also means to chat informally, and has an entirely positive connotation. People get together to kibitz—“visiting with each other”.  A kibitzer is also a person that like to kid around, tell stories, live up the conversation. “He’s a real kibitzer” can mean someone is the life of the party.

I know this is going up against the OED (and Leo Rosten), but:  the Hebrew word root k/b/ts means to gather, especially gather together people. “Kabtseinu yachad m’arba kanfot ha’arets” is part of the three times a day weekday liturgy:  “gather us together from the four corners of the earth”.  The Israeli word “kibbutz” is from this root.  I had always thought that “kibitz” was derived from the Hebrew. Yiddish of course is filled with Hebrew words and words derived from Hebrew.

So I wonder if the two meanings, nosy intruder, and getting together to chat, both meanings in Yiddish, might come from two different languages, one from German, one from Hebrew.

That makes sense; I wonder if it’s been discussed in the literature?