Answer: override

AnswerCrossword Clue
OVERRIDE

Disregard arbitrarily.

OVERRIDE

Reverse, as a veto

OVERRIDE

Nullification

OVERRIDE
Function-canceling setting
OVERRIDE
Annul
OVERRIDETrample down
OVERRIDESupersede
OVERRIDEShow who's boss
OVERRIDEConquer, in a way.
OVERRIDEDisregard.
OVERRIDEVeto
OVERRIDEOutweigh.
OVERRIDEAnnul, as a veto.
OVERRIDEPreempt
OVERRIDENullify
OVERRIDECountermand
OVERRIDESet aside
OVERRIDEGive the thumbs-down to
OVERRIDEVeto a veto