Hidden
WordNet
adjective
(1) Difficult to find
"Hidden valleys"
"A hidden cave"
"An obscure retreat"
(2) 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"
(3) Not accessible to view
"Concealed (or hidden) damage"
"In stormy weather the stars are out of sight"