Slight argument (4)
I believe the answer is:
tiff
'slight argument' is the definition.
(I've seen this before)
This is the entire clue.
(Other definitions for tiff that I've seen before include "A minor quarrel of disagreement" , "Petty squabble" , "A small quarrel or spat" , "A spat or small row" , "Slight argument" .)