expression. Literally means 'a great affair'. In slang it means 'big deal
'. For instance take the following conversation:
Shmuyl: Nu, did you hear that Yossale Berger became rich?
Avrum: A groyse zach, like you could think all I care about in the world is Yossale Berger becoming rich!
Shmuyl: What I wanted to tell you, was that Yossale Berger, that became rich...
Shmuyl: He lost all his money.
Avrum: You don't say! Yossale Berger lost all his money?