all of a sudden

all of a sudden

Unexpectedly and abruptly; suddenly. I was startled when the fire alarm went off all of a sudden. I thought Laura and I were friends, but all of a sudden, she stopped talking to me.
See also: all, of, sudden
Farlex Dictionary of Idioms.

all of a sudden

suddenly. All of a sudden lightning struck the tree we were sitting under. I felt a sharp pain in my side all of a sudden.
See also: all, of, sudden
McGraw-Hill Dictionary of American Idioms and Phrasal Verbs.

all of a sudden

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 also: all, of, sudden
The American Heritage® Dictionary of Idioms by Christine Ammer.

all of a sudden

COMMON If something happens all of a sudden, it happens quickly and unexpectedly. All of a sudden she didn't look sleepy any more. I felt incredibly lonely all of a sudden.
See also: all, of, sudden
Collins COBUILD Idioms Dictionary, 3rd ed.

(all) of a sudden

suddenly.
As a noun sudden is now found only in this phrase, but from the mid 16th century to the early 18th century it was in regular use in the sense ‘an unexpected danger or emergency’.
See also: of, sudden
Farlex Partner Idioms Dictionary

ˌall of a ˈsudden

suddenly and unexpectedly: I was sitting reading my book when all of a sudden the lights went out.
See also: all, of, sudden
Farlex Partner Idioms Dictionary

all of a sudden

Very quickly and unexpectedly; suddenly.
See also: all, of, sudden
American Heritage® Dictionary of the English Language, Fifth Edition.
See also:
  • of a sudden
  • have a (sudden) rush of blood to the head
  • have a rush of blood to the head
  • sudden
  • a (sudden) rush of blood (to the head)
  • a rush of blood
  • have a wild hair to (do something)
  • get a wild hair to (do something)
  • alarm
  • alarm bell