Tip of tusk, just about trunk (5)
I believe the answer is:
torso
'trunk' is the definition.
(both can mean a person's chest)
'tip of tusk just about' is the wordplay.
'tip of' suggests taking the first letters.
'just about' becomes 'or so' (or so can mean roughly or approximately).
The initial letter of 'tusk' is 't'.
't'+'orso'='TORSO'
(Other definitions for torso that I've seen before include "Main part of human body" , "Body without head, neck and limbs" , "Trunk; headless, limbless body" , "Trunk, something unfinished" , "Body, minus its head and limbs" .)