Sudden

sudden
    adj 1: happening without warning or in a short space of time; "a
           sudden storm"; "a sudden decision"; "a sudden cure" [ant:
           {gradual}]
    

Sudden \Sud"den\, a. [OE. sodian, sodein, OF. sodain, sudain, F.
   soudain, L. subitaneus, fr. subitus sudden, that has come
   unexpectedly, p. p. of subire to come on, to steal upon; sub
   under, secretly + ire to go. See {Issue}, and cf.
   {Subitaneous}.]
   1. Happening without previous notice or with very brief
      notice; coming unexpectedly, or without the common
      preparation; immediate; instant; speedy. "O sudden wo!"
      --Chaucer. "For fear of sudden death." --Shak.
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            Sudden fear troubleth thee.           --Job xxii.
                                                  10.
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   2. Hastly prepared or employed; quick; rapid.
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            Never was such a sudden scholar made. --Shak.
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            The apples of Asphaltis, appearing goodly to the
            sudden eye.                           --Milton.
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   3. Hasty; violent; rash; precipitate. [Obs.] --Shak.
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   Syn: Unexpected; unusual; abrupt; unlooked-for.
        [1913 Webster] -- {Sud"den*ly}, adv. -- {Sud"den*ness},
        n.
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Sudden \Sud"den\, adv.
   Suddenly; unexpectedly. [R.]
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         Herbs of every leaf that sudden flowered. --Milton.
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Sudden \Sud"den\, n.
   An unexpected occurrence; a surprise.
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   {All of a sudden}, {On a sudden}, {Of a sudden}, sooner than
      was expected; without the usual preparation; suddenly.
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            How art thou lost! how on a sudden lost! --Milton.
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            He withdrew his opposition all of a sudden.
                                                  --Thackeray.
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60 Moby Thesaurus words for "sudden":
      aback, abrupt, abruptly, accelerated, breakneck, breathless, brisk,
      electrifying, expeditious, extraordinary, fast, fleet, forthwith,
      hasty, headlong, hurried, immediate, impatient, impetuous,
      improbable, impulsive, more than expected, nerve-shattering,
      out-of-the-way, overhasty, panting, past expectation, precipitant,
      precipitate, precipitous, quick, rapid, rash, reckless, rushing,
      shocking, short, speedy, startling, suddenly, surprising, swift,
      unannounced, unanticipated, unanticipatedly, unaware, undivined,
      unexpected, unexpectedly, unforeseeable, unforeseen, unguessed,
      unheralded, unhoped for, unlooked-for, unpredictable, unpredicted,
      unprepared for, unwonted, without warning