With vacuous leader round, time for a drink (5)
I believe the answer is:
lager
'for a drink' is the definition.
(lager is a kind of drink)
'with vacuous leader round time' is the wordplay.
'with vacuous leader' becomes 'lr' (I can't justify this - if you can you should give a lot more credence to this answer).
'round' is an insertion indicator.
'time' becomes 'age' (an age is a period of time).
'lr' going around 'age' is 'LAGER'.
Can you help me to learn more?
(Other definitions for lager that I've seen before include "African camp" , "Light-bodied beer" , "Light-coloured beer" , "Regal kind of beer" , "Local offering" .)