1) One who has the face of an ass
2) One who has an ass for a face
3) One who has the appearance of two protruding buttcheeks just below one's forehead

A multipurpose insult (Note: the person in question's face may bear no resemblence to an ass)

Someone who either A) does something to piss you off or B) does something stupid. Synonomous with jackass, loser, dumbass, idiot, bitch, jerk, etc.

An individual who just happens to be in the unique position of having his face look identical to his ass. In most cases, the face takes on the role of the ass and vice-versa. So, it is not uncommon for an assface to have bad breath and to talk a lot of shit.

noun - a person whose behavior is so completely and utterly atrocious that the only explanation is that the person has an ass for a face and as such must live up (or down as it were) to the face.

(1) A person who, out of lack of intelligence or ignorance is making a fool out of him or her self, (2) Drop-dead ugly