A Donny

Someone who acts and tries to be someone of a higher class or higher age. Commonly seen in freshman, who act like an upper classmen by wearing the senior colors on class color day when they are a freshman. Someone who acts this way in order to get attention and respect from the "older kids".

A Donny (adjective) : Dude Blake, why are you wearing senior colors. Stop being a Donny
A Donny : Rebecca, you freaking Donny. Stop going after seniors.