Poets getting drunk in bar (5)
I believe the answer is:
estop
'bar' is the definition.
(thesaurus)
'poets getting drunk' is the wordplay.
'getting drunk' indicates an anagram.
'poets' with letters rearranged gives 'ESTOP'.
'in' acts as a link.
(Other definitions for estop that I've seen before include "Preclude certain evidence (at law) - bar (archaic)" , "Hinder, preclude (law)" , "Legal term" , "Legally prevent" , "term in law" .)