Robust sort of beer (5)
I believe the answer is:
stout
This clue is a double definition.
'robust' is the first definition.
(similar in meaning)
'sort of beer' is the second definition.
(Other definitions for stout that I've seen before include "tipple" , "Kind of beer" , "Inured to fatigue and hardship" , "Dark beer; of heavy build" , "Portly or stalwart" .)