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

---

Other Word Forms

• unprecedentedly adverb
• unprecedentedness noun

Etymology

Origin of unprecedented

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

Example Sentences

A wide-scale refund program returning this much money would be unprecedented.

From The Wall Street Journal

The Tokyo District Court issued a dissolution order in March last year for the Japanese chapter of the Unification Church, saying it had caused "unprecedented damage" to society.

From Barron's

The breakthrough comes from an unprecedented joint analysis of data from the NOvA experiment in the United States and T2K in Japan.

From Science Daily

Mahmood said she was "taking the unprecedented decision to refuse visas for those nationals seeking to exploit our generosity".

From BBC

Asylum applications to the EU dropped by almost 20 percent in 2025, the bloc's asylum agency said Tuesday -- warning however that a crisis in Iran could result in refugee movements of "unprecedented magnitude".

From Barron's

Related Words

• bizarre
• extraordinary
• fantastic
• miraculous
• new
• remarkable
• singular
• uncommon
• unheard-of
• unique
• unparalleled
• unrivaled
• unusual