conclusive, decisive, determinative, definitive mean bringing to an end. conclusive applies to reasoning or logical proof that puts an end to debate or questioning.

DECISIVE definition: having the power or quality of deciding; putting an end to controversy; crucial or most important. See examples of decisive used in a sentence.

1. Settling a matter or conflict; conclusive: the decisive battle in the war; the decisive piece of evidence in the lawsuit. 2. Characterized by or showing the ability to make decisions quickly and firmly; …

DECISIVE definition: 1. able to make decisions quickly and confidently, or showing this quality: 2. strongly affecting…. Learn more.

If someone is decisive, they have or show an ability to make quick decisions in a difficult or complicated situation. He should give way to a younger, more decisive leader.

Jan 20, 2026 · decisive (comparative more decisive, superlative most decisive) Having the power or quality of deciding a question or controversy; putting an end to contest or controversy; final; conclusive.

de•ci•sive /dɪˈsaɪsɪv/ adj. having the power to decide: The decisive argument was the savings his plan would bring. displaying firmness; resolute: a decisive manner. unquestionable; definite: a decisive …