conclusive

American  

[kuhn-kloo-siv] / kənˈklu sɪv /

adjective

1. serving to settle or decide a question; decisive; convincing.

   conclusive evidence.

   Synonyms:

   definitive

2. tending to terminate; closing.

---

conclusive British  

/ kənˈkluːsɪv /

adjective

1. putting an end to doubt; decisive; final

2. approaching or involving an end or conclusion

---

Other Word Forms

• conclusively adverb
• conclusiveness noun
• nonconclusive adjective
• nonconclusively adverb
• nonconclusiveness noun

Etymology

Origin of conclusive

1580–90; < Late Latin conclūsīvus, equivalent to Latin conclūs ( us ) (past participle of conclūdere to conclude; see conclusion) + -īvus -ive

Explanation

If you've got a theory that you're trying to prove, and you uncover a conclusive piece of evidence, then the case is closed. Conclusive means you've got your answer, you've proved your theory, and there can't be any doubt about it. If want to prove that frogs can speak, and you record a frog reciting "The Midnight Ride of Paul Revere," that would be conclusive evidence for your claim. But if the frog seemed to be mumbling and mainly making regular old frog noises, critics would say that your video was not conclusive. You can also use the word conclusive to describe winning something easily or by a large margin, like when the talent competition judges handed the tap-dancing bear a conclusive victory, and he moved on triumphantly to the finals.

Example Sentences

As in the less conclusive first season, it feels engineered to deliver the characters to happy, or relatively happy, endings, and to send viewers out not regretting their investment of time.

From Los Angeles Times • Apr. 16, 2026

Pakistan's Prime Minister Shehbaz Sharif wrote on X that Islamabad would host delegations from the United States and Iran on Friday "to further negotiate for a conclusive agreement to settle all disputes".

From Barron's • Apr. 8, 2026

The shot was more than 70% effective at preventing the disease in the trial, but not enough people contracted Lyme for the findings to be conclusive.

From The Wall Street Journal • Mar. 27, 2026

"It's not by itself conclusive, but it suggests that maybe the dynamo was in a slightly different regime than today," he said.

From Science Daily • Mar. 21, 2026

“However, I think we have now pretty conclusive evidence on the point. . . We have observed neutrons from targets other than beryllium in just the amount we expected.”

From "Big Science" by Michael Hiltzik

Related Words

• compelling
• convincing
• decisive
• indisputable
• irrefutable
• irrevocable
• precise
• unambiguous
• undeniable
• unmistakable