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Synonyms

assertion

American  
[uh-sur-shuhn] / əˈsɜr ʃən /

noun

  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.


assertion British  
/ əˈsɜːʃən /

noun

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

  2. the act of asserting

"Collins English Dictionary — Complete & Unabridged" 2012 Digital Edition © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012

Other Word Forms

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

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."

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Vocabulary lists containing assertion

Example Sentences

Examples are provided to illustrate real-world usage of words in context. Any opinions expressed do not reflect the views of Dictionary.com.

Cranston confirmed that assertion in a separate interview.

From Los Angeles Times • Apr. 10, 2026

These trends emerged despite the mayor's assertion that London's per capita homicide rate has fallen to its lowest level on record.

From BBC • Apr. 9, 2026

Here is where I’m required to offer a throat-clearing assertion that everyone else’s marriage is a mystery, and that we can never know the depths of love or loathing from the outside.

From Salon • Apr. 8, 2026

This reinforces our assertion that investors, including market makers and oil traders, have no idea how to price oil to reflect war risks.

From Barron's • Apr. 8, 2026

That assertion attracted the full attention of law enforcement officials.

From "Just Mercy" by Bryan Stevenson