Definitive means settling the matter for good. A definitive answer, the definitive biography, definitive proof.
The definitive edition of a work is the one later editions are measured against. Do not confuse it with definite, which merely means clear or certain — a definite answer is unambiguous, and a definitive one closes the question.
1adjectivedefinitiveSettling the matter for good.
“The court's ruling gave a definitive answer to the question of who owned the land.”
definitive is a quality.
Latin definitivus comes from definire, to set bounds to — de plus finis, a limit or end.
Middle French
définitif
English, today
definitive
From Middle French définitif.
Etymology from Wiktionary, CC BY-SA