smart cookie
A clever and intelligent person. Don't underestimate Cindy's intelligence—she's one smart cookie!
a smart cookie
If someone is a smart cookie, they are clever and have good ideas. Anyone who made billions in the Russian oil industry is clearly a smart cookie. Helen's a pretty smart cookie — I trust her.
a/one smart ˈcookie
(American English, informal) a clever person with good ideas: Jed is one smart cookie. I’m sure he’ll do the right thing.