disappointed vs defeated

disappointed is not a noun while defeated is a noun.

Word	Noun	Adjective	Verb	Adverb
disappointed	No	Yes	No	No
defeated	Yes	Yes	No	No

As adjectives, disappointed and defeated are synonyms defined as:

Other synonyms of disappointed include discomfited, foiled, frustrated, thwarted.

disappointed (noun)	defeated (noun)
	people who are defeated

disappointed (adjective)	defeated (adjective)
disappointingly unsuccessful	beaten or overcome; not victorious
	disappointingly unsuccessful