copulation vs nookie

copulation and nookie both are nouns.

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

As nouns, nookie is a hyponym of copulation; that is, nookie 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
nookie: slang for sexual intercourse

copulation (noun)	nookie (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