1. A giver of uninvited or unwanted advice.
2. A spectator at a card game who looks at the players’ cards over their shoulders, especially one who gives unsolicited advice.
3. A person who jokes, chitchats, or makes wisecracks, especially while others are trying to work or to discuss something seriously.
Kibitzer entered English first in America in the 1920s. It comes from the Yiddish word kibetsn (equivalent to German kiebitzen) meaning “to look on at cards.”