1The act of hindering or preventing the discovery, knowledge, or sight of something. 2The hiding or placement of an object out of notice or sight. active concealment.The concealment by deeds or speech of something that one has a duty to reveal. fraudulent concealment. The failure to inform another of a material fact that one has a duty to reveal, with the intention that the other party rely upon the omission to his or her detriment. passive concealment. The concealment of something by maintai...