Covert, obscured (6)
I believe the answer is:
hidden
This clue is a double definition.
'covert' is the first definition.
(similar in meaning)
'obscured' is the second definition.
(I've seen this before)
(Other definitions for hidden that I've seen before include "Unseen" , "Consealed or secret" , "Not accessible to view" , "Covert, obscured" , "Obscure" .)