Dismembered body thus placed on hill (5)
I believe the answer is:
torso
'dismembered body' is the definition.
(central part of body excluding limbs and head)
'thus placed on hill' is the wordplay.
'thus' becomes 'so' (synonyms).
'placed on' says to put letters next to each other.
'hill' becomes 'tor' (tor is a kind of hill).
'so' after 'tor' is 'TORSO'.
(Other definitions for torso that I've seen before include "Poorly-dressed child" , "Roost (anag)" , "Body (excluding head, neck and limbs)" , "unfinished work" , "Trunk, something unfinished" .)