Tolerate ecstasy in drinking establishment (4)
I believe the answer is:
bear
'tolerate' is the definition.
('bear' can be a synonym of 'tolerate')
'ecstasy in drinking establishment' is the wordplay.
'ecstasy' becomes 'e' (informal term for the drug).
'in' indicates putting letters inside.
'drinking establishment' becomes 'bar' (I've seen this before).
'e' going within 'bar' is 'BEAR'.
(Other definitions for bear that I've seen before include "Abide; support" , "One's hairy" , "Endure - mammal" , "Give birth to - large mammal" , "Brook" .)