G.I. Jimbo 

The less buff, less handsome, gawky looking G.I. Joe that has no military experience and thinks his machine gun shoots nerf balls.

Also used to describe a jock wannabe.

Look at him in that football uniform, pretending he knows what he's doing. What a G.I. Jimbo.

G.I. Jimbo by ~*erin*~ April 10, 2004