Billy Bicep 

A person that primarily works their upper body in the weight room, typically their arms. They have usually large arms, abs, and sometimes a larger chest, while lacking legs and other muscles that are challenging to hit. Often wear sweat pants to the weight room to hide their small legs.

Look at that Billy Bicep over there doing curls.

The situation is a Billy Bicep.

That Billy Bicep over there has some serious chicken legs.

Billy Bicep by Billy Bicep June 5, 2010