sexual relation vs intercourse

sexual relation and intercourse both are nouns.

Word	Noun	Adjective	Verb	Adverb
sexual relation	Yes	No	No	No
intercourse	Yes	No	No	No

As nouns, sexual relation and intercourse are synonyms defined as:

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

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