conclusive
UK: kənˈkluːsɪv | US: kənˈkluːsɪv
adj. serving to prove or decide a question; decisive
adj. (of evidence or reasoning) leaving no doubt; convincing
Derived from Latin conclusivus, from concludere (to shut up, conclude), combining con- (together) and -cludere (to shut). The root clus reflects the idea of "shutting" or "ending" something definitively, which evolved into the modern sense of providing a decisive resolution. The suffix -ive turns it into an adjective, emphasizing the quality of being final or irrefutable.
The DNA test provided conclusive evidence of his innocence.
Her argument was so conclusive that no one dared to disagree.
The study lacks conclusive data to support its claims.
The judge demanded more conclusive proof before ruling.
After months of research, they reached a conclusive answer.