Synonyms for Determinative:

adj.

conclusive (adjective)
crucial, decisive, definitive, determinant, determining, final.
final (adjective)
conclusive, final.

n.

authoritative, conclusive, decide, definitive, final. important. communication (noun)
determiner.
determinative (noun)
causal factor, crucial, deciding, decisive, determinant, determiner, determining factor, determining.

Other synonyms:

definitive, final. authoritative. Other relevant words:
authoritative, conclusive, decide, definitive, final, important.

Usage examples for determinative

  1. The earliest Egyptian hieroglyphic sign for gold was a picture of a necklace of such amulets; and this emblem became the determinative of the Great Mother Hathor, not only because she was originally the personification of the life- giving shells, but also because she was the guardian deity both of the Eastern wadys where the gold was found and of the Red Sea coasts where the cowries were obtained. – The Evolution of the Dragon by G. Elliot Smith
  2. The second stage excludes phonetic corruption in the principal root, but allows it in the secondary or determinative elements. – Lectures on The Science of Language by Max Müller
  3. It loses itself in dicta, as determinative in detail for the weal or woe of mankind as they are disconnected in themselves and dissociated from any general doctrine, or even from any especial dogma. – The New Germany by George Young