Hand gin back? (4)
I believe the answer is:
part
'hand' is the definition.
(thesaurus)
'gin back?' is the wordplay.
'gin' becomes 'trap' (I've seen this before).
'back?' says the letters should be written backwards (I've seen 'back' mean this).
'trap' written backwards gives 'PART'.
(Other definitions for part that I've seen before include "Piece, segment" , "Piece; divide" , "Constituent - something to play?" , "Portion of a whole" , "character on > stage" .)