1. Abhorrent; monstrous. He should definitely go to jail for all the heinous crimes he's committed.
2. slang Very bad; terrible. Whoa, that's one heinous hairdo!Your mom won't let you come out with us tonight? Ugh, heinous.
heinous
n. bad; bad-looking; horrible, as in heinous crime. (A standard English word, used in a slangy context.) Where on earth did you get hat heinous outfit?