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

During Thursday’s hearing, the appeals court also questioned Ensign on the DOJ’s assertion that courts should give significant deference to the president’s findings that the conditions required to invoke the enemies act have been met. —Jack Birle, The Washington Examiner, 22 Jan. 2026

But what unfolded over the course of his lengthy speech was less a celebration of economic revival than a sweeping assertion of American dominance—and of his own role as its chief architect—over allies, adversaries and institutions alike. —Nik Popli, Time, 21 Jan. 2026

In this latest case, however, O’Foghludha’s initial ruling against Duke forecloses any comparable assertions by the athlete. —Daniel Libit, Sportico.com, 21 Jan. 2026

His assertion came before any investigation was conducted and before all the facts were known. —Yohuru Williams, Mercury News, 21 Jan. 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