“Kibitz” is a Yiddish verb, meaning to be a spectator who offers often unwanted advice or commentary. A kibitzer, of course, is a person who likes to kibitz.
The term can be applied to any activity, but is most commonly used to describe spectators in games such as contract bridge and chess. In bridge, a kibitzer simply refers to a spectator looking over a player’s shoulder and watching how he plays the hand. Kibitzers in bridge are expected to remain silent and not impact the game.
Kibitz and kibitzer are derived from German kiebitzen, to look over a card-player’s shoulder, perhaps derived from Kiebitz, a lapwing or peewit.
The verb kibitz can also refer to idle chatting or side conversations.
In computer science the term “kibitz” is the title of a programming language that allows two users to share one shell session, taking turns typing one after another.
There is a 1930 film called The Kibitzer which is based on the 1929 three-act comedy play by the same name.
Jane Jacobs describes a kibitzer as someone who keeps a look-out on a street, and seeing suspicious activity, intervenes to help the victim. In this way, kibitzers help keep streets safe.
In the world of bridge, an extension of the standard definition has been added. A kibitzer not only watches a bridge game, but he also has the licence to make comments about the bidding and play — as long as he doesn’t do so while the game is on.
I’m a veteran bridge-player, and I do not permit kibitzers to look over my shoulder. The presence of a kibitzer disrupts my concentration, especially if I hear a gasp when I make an odd play. Besides, if this person is so interested in the game, he or she can go find a partner and get involved. It’s very seldom that blood is spilled.