Arrogance, it's said, developing during row (7)
I believe the answer is:
disdain
'arrogance' is the definition.
(I've seen this before)
'said developing during row' is the wordplay.
'developing' indicates anagramming the letters.
'during' means one lot of letters goes inside another.
'row' becomes 'din' (both can mean a loud disturbance).
'said' is an anagram of 'sdai'.
'sdai' inserted into 'din' is 'DISDAIN'.
'it's' is the link.
(Other definitions for disdain that I've seen before include "Arrogance" , "Contumely" , "'Contempt, condescension (7)'" , "Contempt for something unworthy of notice" , "Haughtiness" .)