Forbids public houses serving drink (4)
I believe the answer is:
bars
'forbids' is the definition.
(barring is a kind of forbiding)
I can't explain the remainder of the clue.
Can you help me to learn more?
(Other definitions for bars that I've seen before include "Establishments where alcoholic drinks are served" , "where people get drunk" , "Rods or drink dispensers" , "Excludes; sandbanks" , "Watering holes - units in musical scores" .)