poker game vs high-low

poker game and high-low both are nouns.

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

As nouns, high-low is a hyponym of poker game; that is, high-low is a word with a more specific, narrower meaning than poker game:

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

Other hyponyms of poker game include draw, draw poker, penny ante, penny ante poker, straight poker, strip poker, stud, stud poker.

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