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

• 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

There’s been a misguided assertion that what’s happening with ICE is only a Latino issue, but ICE’s bombardment of both Black and Brown communities in Chicago demonstrates otherwise. —Andre Gee, Rolling Stone, 21 Oct. 2025

The Kinahans soon tested the strength of that assertion. —Ed Caesar, New Yorker, 20 Oct. 2025

Scientists, meteorologists, and other branches of the federal government say these assertions are largely incorrect. —Stephanie Armour, CNN Money, 16 Oct. 2025

The administration has not made public any evidence to support those assertions. —Luis Martinez, ABC News, 16 Oct. 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