An example of an attagirl is when your boss tells everyone at the meeting that you did a great job on your last project.
Origin of attagirlprobably ; from that's the girl! by analogy with attaboy
Origin of attagirlAlteration of That's the girl!.
- (idiomatic, colloquial) Used to show encouragement or approval to a girl or woman. Female version of attaboy.