Body part temperature given approximately (5)
I believe the answer is:
torso
'body' is the definition.
(a person's middle)
'part temperature given approximately' is the wordplay.
'part' indicates taking the first letters.
'given' means one lot of letters go next to another.
'approximately' becomes 'or so' (synonyms).
The initial letter of 'temperature' is 't'.
't'+'orso'='TORSO'
(Other definitions for torso that I've seen before include "Chest" , "Roots (anag)" , "Body without head, neck and limbs" , "unfinished work" , "upper body" .)