A drink before the play (5)
I believe the answer is:
Here is my best explanation:
'the play' is the definition.
('drama' can be a synonym of 'play')
'a drink before' is the wordplay.
'drink' becomes 'dram' (I've seen this before**).
'before' means one lot of letters go next to another.
'a' put after 'dram' is 'DRAMA'.
(Other definitions for drama that I've seen before include "Plays as a genre", "Stage production", "Histrionics?", "Literary play", "shared interest of 6 & 12 [VERDI & SHAKESPEARE]", "Spectacle", "theatre performance", "Plays as branch of literature", "Emotional scene" and "Theatrical performance".)