Duh, It's When Everyone Know Everything

Ava: Duh, I can do it.
Dad: What did you say?
Ava: I can do it.
Dad: No, before that.
Ava: Duh.
Dad: Where did you hear that word?
Ava: At school. Rachael says it.
Dad: Well, that's not a nice word to say.
Ava: It's not a bad word.
Dad: No...it's not, but it's still not a nice word to say.
Ava: Why?
Dad: Well...actually, it's not even a real word. Do you even know what it means?
Ava: It's when everyone knows everything.

(dad stops to appreciate Ava's pretty spot on definition)

Dad: Just don't say it.
Ava: Ok.