Offer victory and rule note out (9)
I believe the answer is:
volunteer
'offer' is the definition.
(I know that offer can be written as volunteer)
'victory and rule note out' is the wordplay.
'victory' becomes 'v'.
'and' is a charade indicator (letters next to each other).
'out' indicates anagramming the letters (out can mean wrong or inaccurate).
'rule'+'note'='rulenote'
'rulenote' is an anagram of 'olunteer'.
'v'+'olunteer'='VOLUNTEER'
(Other definitions for volunteer that I've seen before include "Willing (or unpaid) worker" , "One offering to perform unasked" , "Step forward" , "Without being asked" , "tender service" .)