Adroit bishop covered in beer (4)
I believe the answer is:
able
'adroit' is the definition.
(I've seen this in another clue)
'bishop covered in beer' is the wordplay.
'bishop' becomes 'B' (abbreviation for bishop in chess).
'covered in' is an insertion indicator.
'beer' becomes 'ale' (type of beer).
'b' going within 'ale' is 'ABLE'.
(Other definitions for able that I've seen before include "Talented" , "showing talent" , "accomplished" , "Having great proficiency or intelligence" , "Having the power, skill or means (to do something)" .)