2.) A guy who has a history of cheating.
3.) A guy who's just in it for the sex: no being tied down, will ditch as soon as the chick starts to get attached. Basically, they only want casual sex and no serious relationships of any sort.
A young male who has tries to get as much action as possible. He may have 5 girlfriends, 3 friends with benefits, and 4 random hook ups in the course of one week. He never forms any emotional attachment and makes his way out of the relationship at any evidence of attachment from the girl. His standards are rarely high and he doesn't care too much about appearance or personality, as long as you put out.