copulation vs sex act

copulation and sex act both are nouns.

Word	Noun	Adjective	Verb	Adverb
copulation	Yes	No	No	No
sex act	Yes	No	No	No

As nouns, copulation and sex act are synonyms defined as:

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

copulation (noun)	sex act (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