See more synonyms for sudden on
  1. happening, coming, made, or done quickly, without warning, or unexpectedly: a sudden attack.
  2. occurring without transition from the previous form, state, etc.; abrupt: a sudden turn.
  3. impetuous; rash.
  4. Archaic. quickly made or provided.
  5. Obsolete. unpremeditated.
  1. Literary. suddenly.
  1. Obsolete. an unexpected occasion or occurrence.
  1. all of a sudden, without warning; unexpectedly; suddenly.Also on a sudden.

Origin of sudden

1250–1300; Middle English sodain (adj. and adv.) < Middle French < Latin subitāneus going or coming stealthily, equivalent to subit(us) sudden, taking by surprise (see subito) + -āneus composite adj. suffix, equivalent to -ān(us) -an + -eus -eous
Related formssud·den·ly, adverbsud·den·ness, noun

Synonyms for sudden

See more synonyms for on
1, 2. unforeseen, unanticipated. Sudden, unexpected, abrupt describe acts, events, or conditions for which there has been no preparation or gradual approach. Sudden refers to the quickness of an occurrence, although the event may have been expected: a sudden change in the weather. Unexpected emphasizes the lack of preparedness for what occurs or appears: an unexpected crisis. Abrupt characterizes something involving a swift adjustment; the effect is often unpleasant, unfavorable, or the cause of dismay: He had an abrupt change in manner. The road came to an abrupt end.

Antonyms for sudden

1, 2. gradual, foreseen. Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2018

British Dictionary definitions for all of a sudden


  1. occurring or performed quickly and without warning
  2. marked by haste; abrupt
  3. rare rash; precipitate
  1. archaic an abrupt occurrence or the occasion of such an occurrence (in the phrase on a sudden)
  2. all of a sudden without warning; unexpectedly
  1. mainly poetic without warning; suddenly
Derived Formssuddenness, noun

Word Origin for sudden

C13: via French from Late Latin subitāneus, from Latin subitus unexpected, from subīre to happen unexpectedly, from sub- secretly + īre to go
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 all of a sudden



late 13c., perhaps via Anglo-French sodein, from Old French subdain "immediate, sudden," from Vulgar Latin *subitanus, variant of Latin subitaneus "sudden," from subitus "come or go up stealthily," from sub "up to" + ire "come, go." Phrase all of a sudden first attested 1680s, earlier of a sudayn (1590s), upon the soden (1550s). Sudden death, tie-breakers in sports, first recorded 1927; earlier in reference to coin tosses (1834).

Online Etymology Dictionary, © 2010 Douglas Harper

Idioms and Phrases with all of a sudden

all of a sudden

Entirely without warning, abruptly, as in All of a sudden the lights went out. In Shakespeare's day the common phrase was of a sudden, the word all being added in the late 1600s. Also see all at once, def. 2.


see all of a sudden.

The American Heritage® Idioms Dictionary Copyright © 2002, 2001, 1995 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company.