Cut GP discussed (4)
I believe the answer is:
dock
'cut' is the definition.
(I know this)
'gp discussed' is the wordplay.
'gp' becomes 'doc' (I've seen this in other clues).
'discussed' indicates a 'sounds like' (homophone) clue.
'doc' is a homophone of 'DOCK'.
(Other definitions for dock that I've seen before include "Court enclosure; weed" , "Where the accused is placed in court" , "Court enclosure; plant" , "Take pay from" , "Use this for nettle stings" .)