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

• affirmation
• asseveration
• avouchment
• avowal
• claim
• declaration
• insistence
• profession
• protestation

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

Kennedy himself has a history of promoting vaccine misinformation, having repeatedly claimed vaccines cause autism, an assertion that has been widely debunked by science and data. —Omer Awan, Forbes.com, 3 May 2025

But its assertions are characteristic of the Trump administration’s systemic denial of trans lives, and signal further movement by HHS toward policies that seek to suppress trans identities among young people. —Samantha Riedel, Them., 1 May 2025

Trump has implemented sweeping change under the assertion of mass deportations and imposed laws to further his plan. —Anna Commander, MSNBC Newsweek, 1 May 2025

The older sister of the two brothers is also rejecting the initial assertion from authorities about their deaths. —Chris Spargo, People.com, 30 Apr. 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