Hide it well? Take it apart and store it separately if you must. I still live with my parents and I hide my gun in my tennis bag with all my racquets and such.
I also take the next step so when I'm not using my gun it has a barrel sock on, the chamber is empty, and the mags have been removed. If need be I'd put a trig lock on the thing if my parents were that paranoid.
If you are so so worried about someone finding it rent out a space at a self storage unit or purchase a safe. Simple but pricey solutions.