sexual activity vs sluttish

sexual activity is a noun but sluttish is not a noun.

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

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

sexual activity (adjective)	sluttish (adjective)
	casual and unrestrained in sexual behavior
	characteristic of or befitting a slut or slattern; used especially of women