- happening, coming, made, or done quickly, without warning, or unexpectedly: a sudden attack.
- occurring without transition from the previous form, state, etc.; abrupt: a sudden turn.
- impetuous; rash.
- Archaic. quickly made or provided.
- Obsolete. unpremeditated.
- Literary. suddenly.
- Obsolete. an unexpected occasion or occurrence.
- all of a sudden, without warning; unexpectedly; suddenly.Also on a sudden.
- occurring or performed quickly and without warning
- marked by haste; abrupt
- rare rash; precipitate
- archaic an abrupt occurrence or the occasion of such an occurrence (in the phrase on a sudden)
- all of a sudden without warning; unexpectedly
- mainly poetic without warning; suddenly
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).
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.