grown ass kid 

A guy who acts like a kid. Doesn't mean he's immature just has the heart of a little kid because he never had that well of a childhood...

Kanye West - Through the Wire

And I still won't grow up
I'm a grown ass kid
Swear I should be locked up for stupid shit that i did

grown ass kid by some polak October 27, 2004

Grown ass kid 

Someone who is still a kid but acts like a grownup. They do everything like a grown up and don't take directions from other people.

That little girl is a grown ass kid.

Grown ass kid by Nouranne the scammer January 21, 2017

Grown Ass Kid 

Somebody who think they grown but they still live wit they parents,aint got no job, cant pay a single bill,cant take care of responsibliltys like a grown man would.........still act like a lil kid all together.

Girl he said,"Wat u wanna do about it cuz i cant miss school to take u 2 da doctors!"

An i replied,"But u can miss school to get down but u cant 2 handle buisness, i swear i aint never heard of a Grown Ass Kid on da real!"

Grown Ass Kid by Nicole Green December 29, 2006