Synonyms for Conclusive:

adj.

absolute (adjective)
absolute, categorical, certain, complete, consummate, definite, indubitable, perfect, positive, supreme, sure, unconditional, undeniable, unequivocal, unmitigated, unqualified, unrestricted, utter.
authoritative (adjective)
definitive.
certain (adjective)
absolute.
clean (adjective)
entire.
complete (adjective)
accomplished, all, collective, comprehensive, done, entire, exhaustive, final, finished, full, intact, integral, plenary, solid, sum, thorough, through, total, unabridged, uncut, undivided, unified, universal, whole, unsevered, complete.
definite, final (adjective)
absolute, convincing, deciding, decisive, demonstrative, determinative, indisputable, irrevocable, resolving, revealing, settling, telling, unambiguous, unanswerable, unconditional, undeniable, unmistakable, unquestionable.
entire (adjective)
all-embracing, all-inclusive, full-fledged, full-grown, full-scale, global, gross, holistic, mass, sweeping, tally, all, complete, comprehensive, entire, exhaustive, full, sum, total, whole.
final (adjective)
closing, concluding, decisive, last, deciding, demonstrative, determinative, determining, final, indisputable, irrevocable, resolving, revealing, settling, telling, unanswerable, unmistakable, unquestionable.
last (adjective)
concluding.
permanent (adjective)
irrevocable.
persuasive (adjective)
convincing.
positive (adjective)
positive.

n.

circumstantial, corroborative, documentary, inadmissible, reflective, suggestive, supporting, symptomatic, the proof of the pudding (is in the eating). crucial, decide, deciding, determinative, important. authoritative. official, sanctioned, standard, true. conclusive (noun)
absolute, convincing, definitive, determinate, unambiguous, unequivocal, univocal.

Other synonyms:

circumstantial, corroborative, determinative, inadmissible. sanctioned, supporting, symptomatic. crucial, documentary, reflective, suggestive. authoritative, official. conclusive
demonstrative.
deciding
determining.
determining
deciding.
Other relevant words:
authoritative, circumstantial, convincing, corroborative, crucial, deciding, definitive, demonstrative, determinate, determinative, determining, documentary, indisputable, irrevocable, official, reflective, resolving, revealing, sanctioned, settling, standard, suggestive, symptomatic, telling, true, unambiguous, unanswerable, univocal, unmistakable, unquestionable.

Usage examples for conclusive

  1. Was it not only forty- eight hours since, in Paris, Meynell had told her that he had received conclusive evidence of the Scotch marriage, and that Hester was merely Philip's victim, not his wife? – The Case of Richard Meynell by Mrs. Humphrey Ward
  2. If, in the case of the California Colony at Fort Romie, when seventeen out of the original number of families taken from the city, left on account of the lack of water, the next group of settlers had again been chosen from the city, after water had been secured, a more conclusive experiment would have resulted, but instead, the second group were, " farmers by profession." – The Social Work of the Salvation Army by Edwin Gifford Lamb
  3. It is not quite conclusive Den, but it's jolly cute. – The Mystery of the Green Ray by William Le Queux