Withhold (4)
'withhold' is the definition.
(denying is a kind of withholding)
This is the entire clue.
(Other definitions for deny that I've seen before include "Gainsay" , "Refute, contradict" , "Refuse to admit the truth" , "Reject as true" , "Refuse to acknowledge" .)
'withhold' is the definition.
(reserving is a kind of withholding)
This is all the clue.
(Other definitions for reserve that I've seen before include "Keep for future use" , "One on bench" , "Husband - substitute" , "Keep for someone - spare bod" , "put to one side" .)