nasty vs sexual activity

nasty is not a noun while sexual activity is a noun.

Word	Noun	Adjective	Verb	Adverb
nasty	No	Yes	No	No
sexual activity	Yes	No	No	No

nasty (noun)	sexual activity (noun)
	activities associated with sexual intercourse

nasty (adjective)	sexual activity (adjective)
offensive or even (of persons) malicious
exasperatingly difficult to handle or circumvent
disgustingly dirty; filled or smeared with offensive matter
characterized by obscenity