Hate half hour sitting in seedy bar (5)
I believe the answer is:
abhor
'hate' is the definition.
(abhorring is a kind of hating)
'half hour sitting in seedy bar' is the wordplay.
'half' suggests halving the letters.
'sitting in' indicates putting letters inside.
'seedy' indicates an anagram (I've seen this in other clues).
'hour' cut in half is 'ho'.
'bar' with letters rearranged gives 'abr'.
'ho' going within 'abr' is 'ABHOR'.
(Other definitions for abhor that I've seen before include "Not like" , "can't stand" , "Abominate" , "Detest, hate" , "Can't bear" .)