Answer: decisive

AnswerCrossword Clue
DECISIVEResolute
DECISIVELike a tiebreaker
DECISIVECritical
DECISIVEIndisputable
DECISIVEFinal.
DECISIVENot wishy-washy
DECISIVELike Napoleon's defeat at Waterloo
decisivehaving the power to decide
decisivedefinite
decisivedisplaying firmness