Beer around a coat (5)
I believe the answer is:
paint
'coat' is the definition.
(painting is a kind of coating)
'beer around a' is the wordplay.
'beer' becomes 'pint' (beer is typically served by the pint).
'around' means one lot of letters goes inside another.
'pint' going around 'a' is 'PAINT'.
(Other definitions for paint that I've seen before include "Colouring substance" , "Inapt (anag)" , "Apply a coat of colour" , "Use a brush on canvas" , "Colouring matter for decoration" .)