Obeselete is a term for people who have become useless because they are fat. It can be used as a noun or an adjective. This could be because they are too fat to move, or because they are too fat to do their given profession, etc.
A person, usually female, who is fat but doesn't know it, or refuses to believe it. An obeserexic person will most likely where tight clothes, not knowing that all their blubber hangs out.
Did you see that chick Jasmine? She's huge, and she waswearing a shirt that was at least five sizes too small! She's so obeserexic.