poker vs straight poker

poker and straight poker both are nouns.

Word	Noun	Adjective	Verb	Adverb
poker	Yes	No	No	No
straight poker	Yes	No	No	No

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

poker: any of various card games in which players bet that they hold the highest-ranking hand
straight poker: poker in which each player gets 5 cards face down and bets are made without drawing any further cards

Other hyponyms of poker include draw, draw poker, high-low, penny ante, penny ante poker, strip poker, stud, stud poker.

poker (noun)	straight poker (noun)
any of various card games in which players bet that they hold the highest-ranking hand	poker in which each player gets 5 cards face down and bets are made without drawing any further cards
fire iron consisting of a metal rod with a handle; used to stir a fire