Denies access to (4)
I believe the answer is:
bars
'denies access to' is the definition.
(I've seen this in another clue)
This is all the clue.
(Other definitions for bars that I've seen before include "Obstacles" , "Prohibits; sandbanks" , "Rods or drink dispensers" , "Establishments where alcoholic drinks are served" , "Prohibits; pubs" .)