Denied out of hand? Really! (6)
I believe the answer is:
indeed
'really' is the definition.
('indeed' can be a synonym of 'really')
'denied out of hand?' is the wordplay.
'out of hand?' indicates anagramming the letters (I've seen 'out of hand' mean this).
'denied' is an anagram of 'INDEED'.
(Other definitions for indeed that I've seen before include "Absolutely" , "In reality" , "still" , "Truthfully, really" , "Unquestionably" .)