disastrous vs disaster

disastrous is not a noun while disaster is a noun.

Word	Noun	Adjective	Verb	Adverb
disastrous	No	Yes	No	No
disaster	Yes	No	No	No

disastrous (noun)	disaster (noun)
	an act that has disastrous consequences
	an event resulting in great loss and misfortune
	a state of extreme (usually irremediable) ruin and misfortune

disastrous (adjective)	disaster (adjective)
(of events) having extremely unfortunate or dire consequences; bringing ruin