Drinks for the audience is a mistake (5)
I believe the answer is:
lapse
'mistake' is the definition.
(I know that lapse is a type of mistake)
'drinks for the audience' is the wordplay.
'drinks' becomes 'laps' (lapping is a kind of drinking).
'for the audience' shows a homophone (sound like) (how an audience might hear it).
'laps' is a homophone of 'LAPSE'.
'is a' acts as a link.
(Other definitions for lapse that I've seen before include "Careless mistake" , "Pales into omission" , "Brief (memory) failure" , "Fall from grace" , "Error; oversight" .)