Be outstanding; shine (5)
I believe the answer is:
excel
This clue is a double definition.
'be outstanding' is the first definition.
(I've seen this in another clue)
'shine' is the second definition.
(I've seen this in another clue)
(Other definitions for excel that I've seen before include "Be exceptionally good (at a subject)" , "Eclipse" , "Be superior to" , "Be the best" , "Predominate in" .)