Finish with unexpected result (6)
I believe the answer is:
lustre
'finish' is the definition.
(lustre is a kind of finish)
'unexpected result' is the wordplay.
'unexpected' indicates anagramming the letters.
'result' is an anagram of 'LUSTRE'.
'with' acts as a link.
(Other definitions for lustre that I've seen before include "Sheen or renown" , "Polish" , "Reflected light, sheen" , "Soft brightness or glory" , "effect of reflected light" .)