adjective: Relating to or bringing about the settlement of a case.
From dispose, from Old French disposer, from Latin disponere (to arrange), from dis- (apart) + ponere (to put). Ultimately from the Indo-European root apo- (off or away), which is also the source of pose, apposite, after, off, awkward, post, puny, apposite, and apropos. Earliest documented use: 1483.
"The Justice Department subsequently asked the National Academy of Sciences to re-examine the Dictabelt evidence and it concluded it was not dispositive, which naturally led to years of debate among forensic acoustic experts."
Ron Rosenbaum; Seeing Zapruder; Smithsonian (Washington, DC); Oct 2013.

"Marilyn Yalom supplements her summaries of love in French culture with lively, if hardly dispositive, anecdotes from her own encounters with France and the French.
How the French Invented Love; The New Yorker; Feb 4, 2013.

DISPOSILIVE - to resurrect a contention that was thought to be setttled