Body part's temperature given approximately (5)
I believe the answer is:
torso
'body' is the definition.
('torso' can be a synonym of 'body')
'part's temperature given approximately' is the wordplay.
'part' says to take the initial letters.
'given' means one lot of letters go next to another.
'approximately' becomes 'orso' ('or so' can be a synonym of 'approximately').
The first letter of 'temperature' is 't'.
't'+'orso'='TORSO'
(Other definitions for torso that I've seen before include "Body (excluding head, neck and limbs)" , "Roost (anag)" , "Body's core" , "upper body" , "unfinished work" .)