tourney vs round robin

tourney and round robin both are nouns.

Word	Noun	Adjective	Verb	Adverb
tourney	Yes	No	Yes	No
round robin	Yes	No	No	No

As nouns, round robin is a hyponym of tourney; that is, round robin is a word with a more specific, narrower meaning than tourney:

tourney: a sporting competition in which contestants play a series of games to decide the winner
round robin: a tournament in which every contestant plays every other contestant

Other hyponyms of tourney include World Cup, elimination tournament, open.

tourney (noun)	round robin (noun)
a sporting competition in which contestants play a series of games to decide the winner	a letter signed by a number of people
	a tournament in which every contestant plays every other contestant

tourney (verb)	round robin (verb)
engage in a tourney