Sailor in hat a renegade (3)
I believe the answer is:
tar
'sailor' is the definition.
(slang term for a sailor)
'in hat a renegade' is the wordplay.
'in' indicates a hidden word.
'TAR' can be found hidden inside 'hat a renegade'.
(Other definitions for tar that I've seen before include "Thick flammable liquid" , "Black substance in cigarettes" , "Flammable liquid; sailor" , "Mariner, old salt" , "Sticky black stuff" .)