immature 

someone who cannot control their emotional behavior

Some people can act immature when they feel they are attacked.

immature by Gerard Irick March 24, 2010

Immature 

What people who post definitions to this site are best at.

Bob: Hey, did you see that definition on Urban Dictionary?
Frank: Yeah, it was immature at it's best. o_o

Immature by TheOrlyGuyLol January 24, 2010

Immature 

The adjective boring people use to describe fun people.

JK: "Nip slip!"
Maren: "You're so immature"
JK: "You're so boring"
Maren: "I know"

Immature by jmfk November 18, 2014

Immature 

Immature is a person, usually 8-15 year's old, (and mostly male) who think sexual and inappropriate things are funny.
This drives me totally crazy, when your the only kid of you age that is way more mature then everybody else areound you (like me)
They call everything they don't like gay, or retarded, and anybody smarter than them a nerd, because they are to incapable of realizing that they are stupid, and (not to be hypocritical) retarded...

-Immature person- You got high honor roll in school? Hahahha! Your such a gay nerd!

-Civilized person- Your immaturity is making yourself look bad...Not me

Immature by TheJazzKidOfTheSchool666 June 25, 2009

Immature 

Someone who acts annoying and stupid.

95% of 13 year-old Boys.

Immature by Glittery Goddess June 23, 2004

immature 

When someone doesn't look at another's point of view.

I think you should apologise to me (even though I've deeply hurt you).

immature by Peter Smith September 15, 2003

Immature 

People who are annoying, don't know what they are talking about, and sometimes bitch way to much.

Look up Nu-Metal and you'll find many examples of the bitching part of immaturity.

Immature by Drummer November 11, 2004