Resolve to belt criminal (6)
I believe the answer is:
bottle
'resolve' is the definition.
(both can mean determination or boldness)
'to belt criminal' is the wordplay.
'criminal' indicates anagramming the letters.
'to'+'belt'='tobelt'
'tobelt' anagrammed gives 'BOTTLE'.
(Other definitions for bottle that I've seen before include "Pitcher perhaps" , "Glass container or slangy courage" , "Vessel for liquids" , "Container for liquids" , "It keeps drink" .)