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 administration has justified imposing the duties through an assertion that America’s prolific trade imbalance with the rest of the world amounts to a balance-of-payments problem, which the law addresses. —Kate Nishimura, Footwear News, 23 June 2026

What gives us confidence in this assertion? —Rob Toews, Forbes.com, 22 June 2026

Trump did not address Iran’s assertion that the strait is currently closed. —Mithil Aggarwal, NBC news, 20 June 2026

The bill also required more documentation of work and income to participate, despite advocates' assertion that states were already collecting lots of paperwork. —Bart Jansen, USA Today, 19 June 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