hidden

adjectives

not accessible to view
"concealed (or hidden) damage"; "in stormy weather the stars are out of sight"
concealed, hidden, out of sight
designed to elude detection
"a hidden room or place of concealment such as a priest hole"; "a secret passage"; "the secret compartment in the desk"
hidden, secret
difficult to find
"hidden valleys"; "a hidden cave"; "an obscure retreat"
hidden, obscure