A person who has a reputation for getting, or who has actually gotten, their ass kicked in almost every physical altercation they have ever been in, "cement merchant" being indicative of someone who gets knocked down to the ground a lot, and who loses more fights than he/she wins.
"I wouldn't pay that dude running his mouth at you like he's Mr. Tough Guy any mind...he's actually a real cement merchant and probably isn't worth your time."
by Kirk Bradford Myers November 19, 2006