Dexterous or clever (6)
I believe the answer is:
adroit
This clue is a double definition.
'dexterous' is the first definition.
(similar in meaning)
'clever' is the second definition.
(synonyms)
(Other definitions for adroit that I've seen before include "Quick and clever in action or thought" , "Skilful, dexterous" , "Dextrous" , "Clever, skilful" , "Apt" .)