A person or action that is absolutely ridiculous and at the same time pisses you off. Similar to saying "oh my God" but actually directing the words at somebody or something that happened.
1. *Jim hurls a basketball randomly in the air over his back and it somehow finds its way in the basket*
Response (Jim's friend): That was unbelievably homeless.
2. Roberto: Hey Kenny I just cheated off you and got a better test mark than you!
Kenny: That's so damn homeless. You're homeless.