1. A particular individual who sits around all day gaining weight, and who is moronic. From the latin root, fattius oafius.
2. President Taft.
You: Yo, Joe, did you see Jerry at McDonalds
the other day? That fatty had to use his inhaler after every bite.
Joe: Yeah, what a fat oaf.
You: Oh my God, that is one ugly walrus in that picture.
Other guy: That's not a walrus, it's just President Taft's baby picture.