Obstacle in drinking establishment (3)
I believe the answer is:
bar
This clue is a double definition.
'obstacle' is the first definition.
(bar can mean an obstacle or blockage)
'drinking establishment' is the second definition.
(I've seen this before)
'in' is the link.
(Other definitions for bar that I've seen before include "drinking establishment" , "Inn" , "Watering hole" , "saving" , "See 9" .)