fat vs obese

fat is a noun but obese is not a noun.

Word	Noun	Adjective	Verb	Adverb
fat	Yes	Yes	Yes	No
obese	No	Yes	No	No

fat (noun)	obese (noun)
excess bodily weight
a kind of body tissue containing stored fat that serves as a source of energy; it also cushions and insulates vital organs
a soft greasy substance occurring in organic tissue and consisting of a mixture of lipids (mostly triglycerides)

fat (adjective)	obese (adjective)
having an (over)abundance of flesh	excessively fat
containing or composed of fat
marked by great fruitfulness
lucrative
having a relatively large diameter

fat (verb)	obese (verb)
make fat or plump