Beer around a coat (5)
I believe the answer is:
paint
'coat' is the definition.
(paint is a kind of coat)
'beer around a' is the wordplay.
'beer' becomes 'pint'.
'around' indicates putting letters inside.
'pint' placed 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" .)