Debated (6)
I believe the answer is:
argued
'debated' is the definition.
('argue' can be a synonym of 'debate')
This is the entire clue.
(Other definitions for argued that I've seen before include "Rag due (anag.)" , "Contended or debated" , "Sought to show by reasoning" , "Disputed, opposed verbally" , "Disputed - . . . . . . the toss" .)