Origin of attagirlprobably from that's the girl! by analogy with attaboy
The definition of an atta girl is a compliment or words of encouragement given to a girl who has done a good job on something.
An example of an attagirl is when your boss tells everyone at the meeting that you did a great job on your last project.
Informal indicating approval or encouragement: said to a woman or girl
also written atta girl
Used to show encouragement or approval to a girl or woman: Attagirl! That was a great shot!
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.