SUDDENLY
abruptly, suddenly, short, dead
(adverb) quickly and without warning; “he stopped suddenly”
suddenly, all of a sudden, of a sudden
(adverb) happening unexpectedly; “suddenly she felt a sharp pain in her side”
Source: WordNet® 3.1
Etymology
Adverb
suddenly (comparative more suddenly, superlative most suddenly)
Happening quickly and with little or no warning; in a sudden manner.
Synonyms
• all of a sudden
• without warning
Antonyms
• unsuddenly
Source: Wiktionary
SUDDEN
Sud"den, a. Etym: [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.
Sudden fear troubleth thee. Job xxii. 10.
2. Hastly prepared or employed; quick; rapid.
Never was such a sudden scholar made. Shak.
The apples of Asphaltis, appearing goodly to the sudden eye. Milton.
3. Hasty; violent; rash; precipitate. [Obs.] Shak.
Syn.
– Unexpected; unusual; abrupt; unlooked-for.
– Sud"den*ly, adv.
– Sud"den*ness, n.
Sud"den, adv.
Definition: Suddenly; unexpectedly. [R.]
Herbs of every leaf that sudden flowered. Milton.
Sud"den, n.
Definition: An unexpected occurrence; a surprise. All of a sudden, On a
sudden, Of a sudden, sooner than was expected; without the usual
preparation; suddenly.
How art thou lost! how on a sudden lost! Milton.
He withdrew his opposition all of a sudden. Thackeray.
Source: Webster’s Unabridged Dictionary 1913 Edition