Trunk roughly underneath top of tree (5)
I believe the answer is:
torso
'trunk' is the definition.
(both can mean a person's chest)
'roughly underneath top of tree' is the wordplay.
'roughly' becomes 'or so' ('10 or so' can mean 'roughly 10').
'underneath' is a charade indicator (letters next to each other) (in a down clue, some letters go under others).
'top of' suggests taking the first letters.
The initial letter of 'tree' is 't'.
'orso' after 't' is 'TORSO'.
(Other definitions for torso that I've seen before include "Limbless statue" , "part of body will be found" , "Poorly-dressed child" , "Body (excluding head, neck and limbs)" , "Body without head, neck and limbs" .)