Clever clogs (Sting, that is) (7)
I believe the answer is:
smartie
'clever clogs' is the definition.
(both can mean an intelligent person)
'sting that is' is the wordplay.
'sting' becomes 'smart' (I've seen this before).
'that is' becomes 'ie' (short for Latin 'id est', 'that is').
'smart'+'ie'='SMARTIE'
(Other definitions for smartie that I've seen before include "Clever clogs" , "Clever dick" .)