sexual relation vs carnal knowledge

sexual relation and carnal knowledge both are nouns.

Word	Noun	Adjective	Verb	Adverb
sexual relation	Yes	No	No	No
carnal knowledge	Yes	No	No	No

As nouns, sexual relation and carnal knowledge are synonyms defined as:

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

Other synonyms of sexual relation include coition, coitus, copulation, intercourse, relation, sex act, sexual congress, sexual intercourse.

sexual relation (noun)	carnal knowledge (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