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

In an address from the White House tonight, the president sought to reveal proof for his baseless assertions of a 2020 vote marred by fraud. — Michael Scherer, The Atlantic, 17 July 2026

But many of his claims, which echo his assertions after losing the 2020 election, have been debunked by investigations, audits or court proceedings. — Justine McDaniel, Los Angeles Times, 17 July 2026

Officials provided no evidence to support the administration’s assertion that the pool was vandalized. — Maura Judkis, Washington Post, 16 July 2026

Smith agrees with those assertions, and adds that the thickness and dairy-forward flavor make Rita’s top tier. — Karla Walsh, Southern Living, 15 July 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