A house of cards stands for a structure that looks impressive but rests on very little. Dream books read it as worry that a plan, a story or a relationship could collapse at a touch.
When this appeared in your dream, what were you feeling?
My Cosmic Code has a private dream journal. Write a dream down and the app picks out the symbols in it, shows what dream books say about them and, over time, which words recur across your entries. The journal is stored on your device only.