juvinility 

The act of being juvenile; acting annoyingly younger than your age (like you're in high school when you are in your mid-twenties); acting like a douche.

1. Knock off that juvinility right now!
2. Your caring about me negates the juvinility of your behavior.
3. Your juvinility is a poor example to these young adults who are struggling to become mature and productive people.

juvinility by Mattimeo February 14, 2008

Juvinity 

Like virginity. Juvinity is being a juvenile that has not reached the age of 18. You lose your Juvinity on your 18th name day (birthday) and you can never get it back.
-unless time travel is invented.

Marks 18th is on Friday, he is finally losing his Juvinity!

Juvinity by Antisocialwombat January 12, 2014