of a sudden
AdverbWordNet 3.0
Adverb (1)
- happening unexpectedly“suddenly she felt a sharp pain in her side”Synonyms: suddenlyall of a suddenof a sudden
Webster's Dictionary (GCIDE)
Sudden \Sud"den\, n. An unexpected occurrence; a surprise. [1913 Webster]
All of a sudden, On a sudden, Of a sudden, sooner than was expected; without the usual preparation; suddenly. [1913 Webster]
How art thou lost! how on a sudden lost!— Milton.[1913 Webster]
He withdrew his opposition all of a sudden.— Thackeray.[1913 Webster]