Brief result of amateur boxing scam (7)
I believe the answer is:
laconic
'brief' is the definition.
(synonyms)
'amateur boxing scam' is the wordplay.
'amateur' becomes 'laic' (I can't justify this - if you can you should give a lot more credence to this answer).
'boxing' is an insertion indicator ('box' can mean contain, as in to put in a box).
'scam' becomes 'con' (both can mean a fraudulent scheme).
'laic' going around 'con' is 'LACONIC'.
'result of' acts as a link.
Can you help me to learn more?
(Other definitions for laconic that I've seen before include "with little expression" , "Conical (anag) - pithy" , "Saying little" , "'Curt, terse (7)'" , "Spartan" .)