Secret op ban "an abomination" admits CEO (3,6)
I believe the answer is:
top banana
'ceo' is the definition.
'secret op ban an abomination admits' is the wordplay.
'admits' indicates the answer is hidden within the clue.
'TOP BANANA' is hidden within 'secret op ban an abomination'.
(Other definitions for top banana that I've seen before include "Boss (slang)" , "figurehead?" , "Best of the bunch!" , "pick of the bunch?" , "head" .)