Bright, but there's no answer to chopper (6)
I believe the answer is:
clever
'bright' is the definition.
(thesaurus)
'there's no answer to chopper' is the wordplay.
'there's no' suggests deleting specific letters.
'answer' becomes 'a' (abbreviation eg in Q and A).
'to chopper' becomes 'cleaver' ('cleaver' can be a synonym of 'chopper').
'cleaver' with 'a' taken away is 'CLEVER'.
'but' is the link.
(Other definitions for clever that I've seen before include "Bright, quick-witted, intelligent" , "expert" , "Skilful, adroit" , "Quick, skilful" , "brilliant" .)