1. He's a creep. (= unpleasant, suspicious, makes you afraid/uneasy)
2. He's a pervert. (= someone with disgusting sexual tendencies)
3. He's a sicko.
4. He's a scumbag.
5. He's an asshole.
6. He's a jerk.
7. He's a bastard.
8. She's a bitch. (= she's irritating and unpleasant)
9. She's a psycho. (= crazy, irrational)
10. She's a slut. (= she has sex with a lot of people)

Fact
There are more living organisms on the skin of a single human being than there are human beings on the surface of the earth.      .. More >>