Hardly open (5)
I believe the answer is:
cagey
'hardly open' is the definition.
(I've seen this in another clue)
This is all the clue.
(Other definitions for cagey that I've seen before include "guarded" , "Secretive, cautious about giving information" , "not open" , "Keeping things to oneself" , "reluctant to give information" .)