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

So, how does the rest of the longevity world view their assertions? — Mark Ellwood, Robb Report, 9 Aug. 2026

The core assertion is that money in circulation directly reflects production levels, not central bank actions. — John Tamny, Forbes.com, 9 Aug. 2026

Weeks later, China’s Ministry of Justice issued another first-of-its-kind order, declaring that the European Union’s antisubsidy probe into a Chinese security firm was an improper assertion of foreign jurisdiction. — Mark Jia, Foreign Affairs, 7 Aug. 2026

The assertion that generally accepted AI safety practices don’t yet exist is inaccurate. — Chicago Tribune, 6 Aug. 2026

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
• tertian
• overexertion
• reassertion

Kids Definition

assertion

noun

as·​ser·​tion ə-ˈsər-shən 

a-

: the act of asserting

also : something asserted : declaration