card-house vs house of cards

card-house and house of cards both are nouns.

Word	Noun	Adjective	Verb	Adverb
card-house	Yes	No	No	No
house of cards	Yes	No	No	No

As nouns, card-house and house of cards are synonyms defined as:

card-house and house of cards: an unstable construction with playing cards

Other synonyms of card-house include cardcastle, cardhouse.

card-house (noun)	house of cards (noun)
an unstable construction with playing cards	an unstable construction with playing cards
	a speculative scheme that depends on unstable factors that the planner cannot control