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Synonyms

unprecedented

American  
[uhn-pres-i-den-tid] / ʌnˈprɛs ɪˌdɛn tɪd /

adjective

  1. without previous instance; never before known or experienced; unexampled or unparalleled.

    an unprecedented event.

    Synonyms:
    novel, exceptional, extraordinary, unique

unprecedented British  
/ ʌnˈprɛsɪˌdɛntɪd /

adjective

  1. having no precedent; unparalleled

"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

Etymology

Origin of unprecedented

First recorded in 1615–25; un- 1 + precedent + -ed 2

Explanation

Something that is unprecedented is not known, experienced, or done before. If you've never gone on a family beach vacation but you're planning one now, you could refer to it as an unprecedented decision. The root of this word is precedent, a noun referring to something done or said that is used as an example to be followed in the future. In law, a precedent is a legal decision that is used as a standard in future cases. So the adjective unprecedented, meaning "having no precedent," was formed from the prefix un- "not," the noun precedent, and the suffix –ed "having."

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Vocabulary lists containing unprecedented

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.

Since then, the team has enjoyed unprecedented success on and off the court.

From MarketWatch • Jun. 30, 2026

It said there had been "unprecedented" average pay rises and financial incentives offered for "crunch" - a video game industry term for excessive, sometimes unpaid, overtime in the lead-up to a game's release.

From BBC • Jun. 30, 2026

PayPal in the late 1990s allowed peer-to-peer trade on an unprecedented scale but drew swindlers, so its founders developed a digital system to detect fraud.

From The Wall Street Journal • Jun. 29, 2026

Anderson, who has fought in the courts for decades for priest accountability, said “This is unprecedented, and this gives me hope.”

From Los Angeles Times • Jun. 29, 2026

"I am going to do something unprecedented in the history of our kingdom, and I hope you'll prove that it's the right decision."

From "The Belles" by Dhonielle Clayton

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