disappointment vs disappoint

disappointment is a noun but disappoint is not a noun.

Word	Noun	Adjective	Verb	Adverb
disappointment	Yes	No	No	No
disappoint	No	No	Yes	No

disappointment (noun)	disappoint (noun)
an act (or failure to act) that disappoints someone
a feeling of dissatisfaction that results when your expectations are not realized

disappointment (verb)	disappoint (verb)
	fail to meet the hopes or expectations of