A pickup truck, usually a Dodge Ram or any pickup truck that's equally imposing and intimidating, driven by a man who acts like a badass but is secretly riddled with anxiety over having a less-than-adequate member. Thus, he's compensating for this deficiency.
"Did you see Bob's new truck? It's huge!"
"Yeah, well, I've heard he's lacking in a certain area, so the truck essentially a compensation vehicle."