Settled (6)
There are a few possibilities for this:
undebatable
'settled' is the definition.
(settled can mean agreed or decided)
This is the entire clue.
(Other definitions for agreed that I've seen before include "acceptable" , "Acquiesed, concurred" , "very well" , "Jointly decided" , "It's a deal!" .)
'settled' is the definition.
(I've seen this in another clue)
This is all the clue.
(Other definitions for repaid that I've seen before include "no longer outstanding" , "Returned" , "Reimbursed" , "Diaper (anag.)" , "Recompensed" .)