From Middle English sodeyn, sodain, from , from , subdain ("immediate, sudden"), from *subitānus, from , from subitus ("sudden", literally, "that which has come stealthily"), originally the past participle of subīre, from sub ("under") + īre.

• IPA: /ˈsʌdən/, [ˈsʌdn̩]

sudden (comparative suddener, superlative suddenest)

1. Occurring quickly with little or no warning or expectation; instantly.

   The sudden drop in temperature left everyone cold and confused.

   • 1913, Joseph C[rosby] Lincoln, chapter I, in Mr. Pratt’s Patients, New York, N.Y., London: D[aniel] Appleton and Company, →OCLC ↗:

     I stumbled along through the young pines and huckleberry bushes. Pretty soon I struck into a sort of path that, I cal'lated, might lead to the road I was hunting for. It twisted and turned, and, the first thing I knew, made a sudden bend around a bunch of bayberry scrub and opened out into a big clear space like a lawn.

2. (obsolete) Hastily prepared or employed; quick; rapid.
   • 1850, [Alfred, Lord Tennyson], In Memoriam, London: Edward Moxon, […], →OCLC ↗, Canto XIV, page 22 ↗:

     And if along with these should come
     ⁠The man I held as half-divine;
     ⁠Should strike a sudden hand in mine,
     And ask a thousand things of home; […]
     I should not feel it to be strange.

3. (obsolete) Hasty; violent; rash; precipitate.

• (happening quickly) abrupt, precipitous, subitaneous; see also Thesaurus:sudden
• (hasty, rash) hotheaded, impetuous, impulsive; see also Thesaurus:reckless

• (antonym(s) of “happening quickly”): gradual; see also Thesaurus:gradual
• (antonym(s) of “all”): unsudden

• French: soudain, subit
• German: plötzlich, jäh
• Italian: improvviso
• Portuguese: repentino, súbito
• Russian: неожи́данный
• Spanish: repentino, súbito, brusco

sudden

1. (poetic) Suddenly.
   • 1667, John Milton, “Book VII”, in Paradise Lost. […], London: […] [Samuel Simmons], and are to be sold by Peter Parker […]; [a]nd by Robert Boulter […]; [a]nd Matthias Walker, […], →OCLC ↗; republished as Paradise Lost in Ten Books: […], London: Basil Montagu Pickering […], 1873, →OCLC ↗:

     Herbs of every leaf that sudden flowered.

sudden (plural suddens)

1. (obsolete) An unexpected occurrence; a surprise.