Use the noun concealment when you talk about the act of hiding something. The concealment of your terrible haircut is easy — just wear a hat.
Concealment is the process of disguising something or the condition of keeping something private. Secret agents need to focus on concealment all the time, of their identities and sometimes their hair color, citizenship, and activities. A hunter's concealment is important in a different way — she might wear camouflage and stay low and quiet to avoid being seen by the ducks she's hunting. The Old French root word is conceler, "to hide."