[Cealocanth]

Around here, it seems that the new word going around the teenage community is "childish"

meaning, in order of commonality:

stupid
rude
immature
unfair
unpleasant
or as an adjective used to describe someone in authority (ex. You won't let me loiter in the hallways between classes with my twenty other friends? Stop being so childish!)

Other examples include:

Talking in a movie theater? Stop being so childish!

That garbage outside sure smells childish.

First graders have a childish intelligence level.

etc.

Edit: Also, around the gaming community there's "natural", stemming from a "natural twenty" meaning a critical hit.

It's used in the same way "boss" is. Essentially, radical, awesome, unpredictable, victorious, etc.

ex. That backflip you just flawlessly performed was so natural!
A lightning bolt struck right outside my house? How natural was that???