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 company disputes the cancer-causing assertions. —ABC News, 2 Apr. 2026

That term encompasses exaggerated, subjective assertions of optimism that are not intended to be taken as factual, are too general to cause a reasonable investor to rely upon them and are not actionable in securities law. —Michael McCann, Sportico.com, 1 Apr. 2026

Tehran did not immediately respond to this assertion either. —Chantal Da Silva, NBC news, 1 Apr. 2026

Rather than selecting a piece from the royal collection, her decision to wear her own family tiara has often been interpreted as a subtle assertion of personal identity within the constraints of monarchy. —Eloise Moran, InStyle, 31 Mar. 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
• overexertion
• reassertion

Kids Definition

assertion

noun

as·​ser·​tion ə-ˈsər-shən 

a-

: the act of asserting

also : something asserted : declaration