intercourse vs sexual relation

intercourse and sexual relation both are nouns.

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

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

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

intercourse (noun)	sexual relation (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