A Meathead is a sexist, drunken, oaf. Usually they aren't the sharpest guys on the block. They spend their days working out and "getting chics." I lump in any guy that might walk up to a girl in a bar, slap her on the butt, and say "You're so fine, why don't you back that ass up." (I've seriously seen a guy do this, but you also need to see the body language to really grasp a meathead and this guy was pure unadulterated meathead. Even though he could kick my ass six ways from Sunday I couldn't help but burst into laughter)

When said by me, it usually said with a low, growling, caveman-like tone and a pound of my fist on my forehead.