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

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

But owning my desire to withdraw was in itself an assertion.

From Los Angeles Times ● Aug. 13, 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

With obvious pleasure Rosy showed Francis her data, and for the first time he was able to see how foolproof was her assertion that the sugar- phosphate backbone was on the outside of the molecule.

From "Double Helix" by James D. Watson

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

From Salon ● Sep. 1, 2026

This should not be viewed as vindictive because “the government was seeking to protect the public and confirm its prior assertions about Abrego’s criminal activity,” prosecutors wrote.

From Slate ● Aug. 23, 2026

There is no evidence to back up those assertions, medical organizations and mainstream experts say.

From Los Angeles Times ● Aug. 15, 2026

In “A Little More Social” he provides documentation for his assertions by way of charts, graphs and extensive citations, though his material is so sensible that proof seems hardly necessary.

From The Wall Street Journal ● Jul. 29, 2026

For example, the statements “UFOs contain extraterrestrial visitors” and “UFOs are unidentified flying objects” are two entirely different assertions.

From "Innumeracy: Mathematical Illiteracy and Its Consequences" by John Allen Paulos

Related Words

• affirmation
• allegation
• contention
• insistence
• pronouncement