a guy or girl who is just an overprotective scumbag when it comes to dating. It doesn't have to be a boyfriend/girlfriend. It could simply be someone who is arrogant, a jerk, a scumbag, or someone who has no regard to one's friendship/relationship
Boy: let's get coffee sometime, you are awesome to be with!!
Girl: uh.. I don;t know.. my boyfriend wouldn't like that
A roach is simply anyone who shares the same characteristics as a bum. A roach technically is not a bum but anywho who degrades themselves to the status level as a bum.
"Corey did you really just eat that taco off the toilet seat? You're such a roach."