Temperature, roughly, in part of body (5)
I believe the answer is:
torso
'part of body' is the definition.
('torso' is part of 'body')
'temperature roughly' is the wordplay.
'temperature' becomes 't' (abbreviation).
'roughly' becomes 'orso' ('or so' can be a synonym of 'roughly').
't'+'orso'='TORSO'
'in' is the link.
(Other definitions for torso that I've seen before include "Chest" , "Limbless statue" , "upper body" , "part of body will be found" , "Main part of human body" .)