indecent vs sexual activity

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

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

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

indecent (adjective)	sexual activity (adjective)
offensive to good taste especially in sexual matters
offending against sexual mores in conduct or appearance
not in keeping with accepted standards of what is right or proper in polite society