intercourse vs sex activity

intercourse and sex activity both are nouns.

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

As nouns, sex activity is a hypernym of intercourse; that is, sex activity is a word with a broader meaning than intercourse:

intercourse: sexual activity between individuals, especially the insertion of a man's penis into a woman's vagina until orgasm and ejaculation occur
sex activity: activities associated with sexual intercourse

Other hypernyms of intercourse include sex, sexual activity, sexual practice.

intercourse (noun)	sex activity (noun)
sexual activity between individuals, especially the insertion of a man's penis into a woman's vagina until orgasm and ejaculation occur	activities associated with sexual intercourse
communication between individuals