The definition of conclusive is something that puts an end to arguments or that definitively proves something or ends dispute.(adjective)
If there is debate over life on other planets and an alien shows up and tells everyone on earth that there is life on other planets, this visit is an example of conclusive evidence of life on other planets.
See conclusive in Webster's New World College Dictionary
Origin: LL conclusivus < pp. of L concludere, conclude
See conclusive in American Heritage Dictionary 4
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