Being unyielding, a point leads to a quarrel (5)
I believe the answer is:
stiff
'being unyielding' is the definition.
(I've seen this before)
'a point leads to a quarrel' is the wordplay.
'a point' becomes 'S' (South).
'leads to' is a charade indicator (letters next to each other).
'a quarrel' becomes 'tiff' (informal term for an argument).
's'+'tiff'='STIFF'
(Other definitions for stiff that I've seen before include "Difficult" , "One dead" , "Awkward" , "cheat" , "Severe - conventional - dead body" .)