boodle vs cards

As nouns, cards is a hypernym of boodle; that is, cards is a word with a broader meaning than boodle:

• boodle: a gambling card game in which chips are placed on the ace and king and queen and jack of separate suits (taken from a separate deck); a player plays the lowest card of a suit in his hand and successively higher cards are played until the sequence stops; the player who plays a card matching one in the layout wins all the chips on that card
• cards: a game played with playing cards