assertion

American  

[uh-sur-shuhn] / əˈsɜr ʃən /

noun

• assertions
  plural

1. a positive statement or declaration, often without support or reason.

   a mere assertion;

   an unwarranted assertion.

   Synonyms:

   allegation, contention, claim

2. an act of asserting.

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assertion British  

/ əˈsɜːʃən /

noun

1. a positive statement, usually made without an attempt at furnishing evidence

2. the act of asserting

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Other Word Forms

Derived Forms

• misassertion
  noun
• nonassertion
  noun
• overassertion
  noun
• reassertion
  noun
• superassertion
  noun
• assertional
  adjective

Inflected Forms

Nouns

• assertions
  plural

Etymology

Origin of assertion

1375–1425; late Middle English assercion < Latin assertiōn- (stem of assertiō ). See assert, -ion

Explanation

An assertion is a declaration that's made emphatically, especially as part of an argument or as if it's to be understood as a statement of fact. To assert is to state with force. So if someone makes an assertion, they’re not just trying out an idea — they really mean it. An assertion can also be an act that seems to make a statement without words. When your dog urinates in multiple places up and down your block, he's making an assertion of his dominance (also called "marking") over his "territory."

Example Sentences

See Examples For:

assertion assertions

A Paramount spokeswoman declined to comment on Bonta’s assertion.

From The Wall Street Journal ● Aug. 25, 2026

The city’s determination stalling the project “is based on the false assertion that the active golf course, in the middle of a residential neighborhood, is habitat for mountain lions,” he said.

From Los Angeles Times ● Aug. 22, 2026

In response to questions about whether the release supported the president’s assertion, the White House responded with a link to a social media post by U.S.

From Salon ● Aug. 21, 2026

Asked whether he would say sorry for his "disrespectful behaviour" in parliament on Tuesday, the Australian leader said: "I reject the assertion in the question."

From Barron's ● Aug. 12, 2026

But as she walked through the house she thought again and again of Richard’s words, and his assertion that he knew honesty did not come easy for her.

From "Ophie's Ghosts" by Justina Ireland

The Civilian Oversight Commission has said that such assertions are unfounded, and that state law and court precedent require its subpoenas to be upheld.

From Los Angeles Times ● Sep. 7, 2026

A Bilt spokesperson said Warren’s assertions were “incorrect.”

From Salon ● Sep. 1, 2026

A.I.’s most famous people have habits of making big, bold assertions about the technology and then softening them over time.

From Slate ● Sep. 1, 2026

"These are grave assertions that directly impugn the claimants' personal integrity, character, and professional reputation", Lim said, adding that this was a factor in the awarding of the damages.

From BBC ● Jul. 14, 2026

Linton glanced at the memo Terryl had handed him and could see now that it was a set of facts and assertions mirroring what Terryl was telling him—an outline of the case.

From "A Deadly Wandering: A Mystery, a Landmark Investigation, and the Astonishing Science of Attention in the Digital Age" by Matt Richtel

Related Words

• affirmation
• allegation
• contention
• insistence
• pronouncement