unprecedented

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

without previous instance; never before known or experienced; unexampled or unparalleled: an unprecedented event.

Origin of unprecedented

First recorded in 1615–25; un-1 + precedent + -ed2
SYNONYMS FOR unprecedented
Related formsun·prec·e·dent·ed·ly, adverbun·prec·e·dent·ed·ness, noun

Word story

The adjective unprecedented is unremarkable in its formation ( un- + precedent + -ed ) and meaning “without precedent, having no precedent; unparalleled.”
What is remarkable about unprecedented is that the two earliest known citations appear with the spelling unpresidented, with an si. The first use of this word appears in a 1641 speech by John Finch, Speaker of the House of Commons (later Lord Keeper of the Great Seal) and a very partisan supporter of King Charles I, and the second recorded use was made by King Charles himself in 1642 in his reply to Parliament. It is not until the following year that we find the first printed instance of this word spelled correctly, with a ce, in a political pamphlet in opposition to Charles I, written by Henry Parker, a strong supporter of the British Parliament.
Dictionary.com Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2019

British Dictionary definitions for unprecedentedness

unprecedented

/ (ʌnˈprɛsɪˌdɛntɪd) /

adjective

having no precedent; unparalleled
Derived Formsunprecedentedly, adverb
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

Word Origin and History for unprecedentedness

unprecedented


adj.

1620s, from un- (1) "not" + precedented. In common use from c.1760.

Online Etymology Dictionary, © 2010 Douglas Harper