Bar worker keeps whiskey in coat (6)
I believe the answer is:
lawyer
'bar worker' is the definition.
(I've seen this in another clue)
'whiskey in coat' is the wordplay.
'whiskey' becomes 'W' (alpha bravo charlie delta ...).
'in' means one lot of letters goes inside another.
'coat' becomes 'layer' (layering is a kind of coating).
'w' put within 'layer' is 'LAWYER'.
'keeps' acts as a link.
(Other definitions for lawyer that I've seen before include "Legal specialist" , "court worker" , "A solicitor, barrister or the like" , "One provides legal advice" , "One gives legal advice" .)