high-low vs poker game

high-low and poker game both are nouns.

Word	Noun	Adjective	Verb	Adverb
high-low	Yes	No	No	No
poker game	Yes	No	No	No

As nouns, poker game is a hypernym of high-low; that is, poker game is a word with a broader meaning than high-low:

high-low: poker in which the high and low hands split the pot
poker game: any of various card games in which players bet that they hold the highest-ranking hand

Other hypernyms of high-low include poker.

high-low (noun)	poker game (noun)
poker in which the high and low hands split the pot	any of various card games in which players bet that they hold the highest-ranking hand