Taunting upset father in disreputable bar (8)
I believe the answer is:
derisive
'taunting' is the definition.
(thesaurus)
'upset father in disreputable bar' is the wordplay.
'upset' says the letters should be written backwards.
'father' becomes 'sire' ('sire' can be a synonym of 'father').
'in' is an insertion indicator.
'disreputable bar' becomes 'dive'.
'sire' in reverse letter order is 'eris'.
'eris' put inside 'dive' is 'DERISIVE'.
(Other definitions for derisive that I've seen before include "Expressing contempt" , "Contemptuous" , "'Scornful, mocking (8)'" , "Taunting" .)