rummy vs gin rummy

rummy and gin rummy both are nouns.

Word	Noun	Adjective	Verb	Adverb
rummy	Yes	Yes	No	No
gin rummy	Yes	No	No	No

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

rummy: a card game based on collecting sets and sequences; the winner is the first to meld all their cards
gin rummy: a form of rummy in which a player can go out if the cards remaining in their hand total less than 10 points

Other hyponyms of rummy include gin, knock rummy, basket rummy, canasta, meld.

rummy (noun)	gin rummy (noun)
a card game based on collecting sets and sequences; the winner is the first to meld all their cards	a form of rummy in which a player can go out if the cards remaining in their hand total less than 10 points
a chronic drinker

rummy (adjective)	gin rummy (adjective)
beyond or deviating from the usual or expected