Kibitzer

A kibitzer is a spectator at a game, most often a card game such as bridge, or a board game such as chess or Go, who watches play and is expected to keep silent rather than offer advice or comment on the hands or moves in progress. The word comes from Yiddish and traces back further to the German kiebitzen, meaning to look over a card player's shoulder, itself apparently connected to Kiebitz, the German name for the lapwing, a bird known for its noisy, meddling behavior around other creatures' nests. Although the term can be applied loosely to an onlooker at almost any activity, it became firmly attached to the culture of serious card and board games, where a kibitzer who breaks the unwritten rule of silence and comments on a hand is considered to have committed a serious breach of etiquette. The word survives in everyday English mainly through this game-table sense, describing anyone who watches and comments on other people's business from the sidelines.