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

Players and umpires can get a definitive answer when a call is disputed.

From Los Angeles Times • Apr. 4, 2026

“We are in active negotiations with multiple counterparties, but as of today, we’ve not executed a definitive lease agreement,” Fermi Chief Financial Officer Miles Everson said on a conference call Monday morning.

From Barron's • Mar. 30, 2026

Even so, researchers have not reached a definitive conclusion.

From Science Daily • Mar. 30, 2026

The IPL, critics argued, was a domestic proving ground - impressive, but not definitive.

From BBC • Mar. 26, 2026

Without definitive documentary evidence of particular sources we may never know if this research included tribal melodies he later passed off as his own.

From "The Story of Music" by Howard Goodall

Related Words

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