Hurt isn't terribly good (5)
I believe the answer is:
sting
'hurt' is the definition.
(sting is a kind of hurt)
'isn't terribly good' is the wordplay.
'terribly' is an anagram indicator.
'good' becomes 'g' (abbreviation).
'isnt' is an anagram of 'stin'.
'stin'+'g'='STING'
(Other definitions for sting that I've seen before include "con trick" , "Carefully planned trap - scorpion's weapon" , "(Bee) wound" , "The pain caused by bee or nettle" , "Painful wound - confidence trick" .)