Body of rubbish written up thus (5)
I believe the answer is:
torso
'body' is the definition.
('torso' can be a synonym of 'body')
'rubbish written up thus' is the wordplay.
'rubbish' becomes 'rot' (I've seen this before).
'written up' is a reversal indicator.
'thus' becomes 'so' ('so' can be a synonym of 'thus').
'rot' written backwards gives 'tor'.
'tor'+'so'='TORSO'
'of' acts as a link.
(Other definitions for torso that I've seen before include "Piece of bronze" , "Roost on trunk?" , "Poorly-dressed child" , "Trunk of human body" , "upper body" .)