Kept hidden from knowledge or view; concealed, Given to keeping one's thoughts and activities unknown to others; secretive, Beyond ordinary understanding; mysterious, noun_ Something that is kept out of the knowledge or sight of others or is known only to oneself or a few, A method or formula for doing or making something well, especially when not widely known, A concealed piece or suit of armor. Persons fearing assassination sometimes wear such defenses beneath their ordinary dress, transitive verb_ obsolete To keep secret.