cardcastle vs house of cards

cardcastle and house of cards both are nouns.

Word	Noun	Adjective	Verb	Adverb
cardcastle	Yes	No	No	No
house of cards	Yes	No	No	No

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

cardcastle and house of cards: an unstable construction with playing cards

Other synonyms of cardcastle include card-house, cardhouse.

cardcastle (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