copulation vs screwing

copulation and screwing both are nouns.

Word	Noun	Adjective	Verb	Adverb
copulation	Yes	No	No	No
screwing	Yes	No	No	No

As nouns, screwing is a hyponym of copulation; that is, screwing is a word with a more specific, narrower meaning than copulation:

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

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