Ran back to argue, being prejudiced (6)
I believe the answer is:
narrow
'being prejudiced' is the definition.
(I've seen this in another clue)
'ran back to argue' is the wordplay.
'back' shows that the letters should be reversed in order.
'to argue' becomes 'row' (to row with someone is to argue with them).
'ran' reversed gives 'nar'.
'nar'+'row'='NARROW'
(Other definitions for narrow that I've seen before include "Pinched" , "Of limited width" , "Bigoted opinion" , "Thin; taper" , "Of small width, strait" .)