pairing vs coupling

pairing and coupling both are nouns.

Word	Noun	Adjective	Verb	Adverb
pairing	Yes	No	No	No
coupling	Yes	No	No	No

As nouns, pairing and coupling are synonyms defined as:

pairing and coupling: the act of pairing a male and female for reproductive purposes

Other synonyms of pairing include conjugation, mating, sexual union, union.

pairing (noun)	coupling (noun)
the act of pairing a male and female for reproductive purposes	the act of pairing a male and female for reproductive purposes
the act of grouping things or people in pairs	a mechanical device that serves to connect the ends of adjacent objects
	a connection (like a clamp or vise) between two things so they move together