Excelled partly through dishonesty (5)
I believe the answer is:
shone
'excelled' is the definition.
(shine can mean to excel or do well)
'partly through dishonesty' is the wordplay.
'partly' indicates a hidden word (part of the clue is used).
'SHONE' can be found hidden inside 'through dishonesty'.
(Other definitions for shone that I've seen before include "Gleamed" , "Radiated, emitted light" , "Excelled; glowed" , "Sparkled" , "did brilliantly" .)