Very skilled or proficient (5)
I believe the answer is:
adept
I believe this clue is a double definition.
'very skilled' is the first definition.
(I've seen this in another clue)
'proficient' is the second definition.
(synonyms)
(Other definitions for adept that I've seen before include "Deacon" , "Practised" , "Handy" , "Having the skill required" , "Very skilled/proficient" .)