What's behind master negotiator in part? (6)
I believe the answer is:
astern
'what's behind' is the definition.
(I've seen this before)
'master negotiator in part?' is the wordplay.
'in part?' indicates the answer is hidden within the clue (I've seen 'in part' mean this).
'ASTERN' can be found hidden inside 'master negotiator'.
(Other definitions for astern that I've seen before include "Towards back of boat" , "Towards the rear of a ship" , "Behind at sea" , "Aft" , "following behind vessel" .)