sex activity vs obscenely

sex activity is a noun but obscenely is not a noun.

Word	Noun	Adjective	Verb	Adverb
sex activity	Yes	No	No	No
obscenely	No	No	No	Yes

sex activity (noun)	obscenely (noun)
activities associated with sexual intercourse

sex activity (adverb)	obscenely (adverb)
	in a lewd and obscene manner
	to an obscene degree