definitive

American  

[dih-fin-i-tiv] / dɪˈfɪn ɪ tɪv /

adjective

1. most reliable or complete, as of a text, author, criticism, study, or the like.

   the definitive biography of Andrew Jackson.

2. serving to define, fix, or specify definitely.

   to clarify with a definitive statement.

3. having its fixed and final form; providing a solution or final answer; satisfying all criteria.

   the definitive treatment for an infection; a definitive answer to a dilemma.

   Synonyms:

   supreme, ultimate, absolute, complete

4. Biology. providing the environment in which a fully developed parasite is able to reproduce, as is provided by a definitive host.

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noun

1. a defining or limiting word, as an article, a demonstrative, or the like.

2. Philately. a stamp that is a regular issue and is usually on sale for an extended period of time.

definitive British  

/ dɪˈfɪnɪtɪv /

adjective

1. serving to decide or settle finally; conclusive

2. most reliable, complete, or authoritative

   the definitive reading of a text

3. serving to define or outline

4. zoology fully developed; complete

   the definitive form of a parasite

5. 1. (of postage stamps) permanently on sale

   2. (as noun) a definitive postage stamp

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noun

1. grammar a word indicating specificity of reference, such as the definite article or a demonstrative adjective or pronoun

Other Word Forms

• definitively adverb
• definitiveness noun
• nondefinitive adjective
• nondefinitiveness noun
• undefinitive adjective
• undefinitiveness noun

Etymology

Origin of definitive

First recorded in 1350–1400; Middle English, from Old French, from Latin dēfīnītīvus, equivalent to dēfīnīt(us) ( definite ) + -īvus adjective suffix ( -ive )

Example Sentences

Even so, researchers have not reached a definitive conclusion.

From Science Daily • Mar. 30, 2026

What’s Next: Gene Sloan, cruise director for The Points Guy, said investors will get their first definitive read on what impact the war is having, or not having, when Carnival reports first-quarter earnings on Friday.

From Barron's • Mar. 24, 2026

It is unhygienic, but there is no definitive proof it is responsible and is hardly unusual behaviour.

From BBC • Mar. 20, 2026

And Tirel is very much inspired by Henri Soulé, whose Le Pavillon was the definitive New York restaurant for a generation, and whom Greene wrote about beautifully.

From Los Angeles Times • Mar. 19, 2026

At last he set his cup down with a final, definitive click against the saucer.

From "The Great Santini" by Pat Conroy

Related Words

• actual
• categorical
• clear-cut
• conclusive
• decisive
• definite
• exhaustive
• precise
• reliable
• specific
• ultimate
• unambiguous