someone who usually pisses everyone off; maybe someone who is a pain in the ass e.g. - retard, fuckface, etc.: the choad reference is a penis that is wider than it is longer, something undesirable; people usually add face after everything...hence choadface
Sara: Hey. Look at Lindsay Lohan. She just gave us another crotch shot.
Joe: Wow. Really. I wonder why she still does that. What a choadface.