A person who is
slow of wit and
vulgar or
ill-mannered. This term is inspired by the
ape: dumb, vulgar creatures (by human standards, of course) whose arms are long enough to touch the ground while locomoting, thus dragging their
knuckles.
For more information, ask a bouncer at you favourite club or bar or Mike Tyson. Be prepared to run away on the off chance that they know what the term means.