assertion

noun

as·​ser·​tion ə-ˈsər-shən 

a-

: the act of asserting or something that is asserted: such as

a

: insistent and positive affirming, maintaining, or defending (as of a right or attribute)

an assertion of ownership/innocence

b

: a declaration that something is the case

He presented no evidence to support his assertions.

Synonyms of assertion

• declaration
• claim
• insistence
• allegation

Examples of assertion in a Sentence

the assertion that all men have certain unalienable rights is set forth in the Declaration of Independence

made the unlikely assertion that gravity affects light

Recent Examples on the Web

The assertions came despite a lack of clear scientific evidence, and Kenvue has called them simply false. —NPR, 4 Nov. 2025

View in new tab Absent from the complaint is any formal assertion that the school violated students' First Amendment rights. —Taylor Seely, AZCentral.com, 4 Nov. 2025

The judge rejected Oakley’s assertion that the hourly rates are too high on account of the lawyers being overqualified. —Michael McCann, Sportico.com, 3 Nov. 2025

The true-crime trappings offered a pointed tool for presenting evidence that contradicted the husbands’ oblivious assertions. —Paula Mejía, The Atlantic, 2 Nov. 2025

Word History

Etymology

see assert

First Known Use

15th century, in the meaning defined above

Phrases Containing assertion

• self-assertion

Rhymes for assertion

• cistercian
• coercion
• desertion
• exertion
• insertion
• mercian
• overexertion
• reassertion

Kids Definition

assertion

noun

as·​ser·​tion ə-ˈsər-shən 

a-

: the act of asserting

also : something asserted : declaration