People in their twenty's who emulate the younger version known as teeny boppers. They dress in strange and loud fashion, hang out in awkward places and want so desperately to belong and be cool. The main difference between twenty boppers and teeny boppers is that twenty boppers are incredibly and unforgivably pretentious. Another name is hipster.
I couldn't stand the little group of twenty boppers in front of me at Starbucks.