before you can say Jack Robinson

English

Etymology

Uncertain. There is some speculation that this is a reference to Sir John Robinson, the Lieutenant of the Tower of London from 1660 to 1680 and Lord Mayor of London in 1662, but there is nothing known about him that is associated with speed (Samuel Pepys called him as “a talking bragging bufflehead.”), and the phrase does not appear in print until 1778.

Phrase

before you can say Jack Robinson

Very quickly; quicker than one expects.
Synonym: before you can say knife

You have to be careful in that area. They'll have your wallet before you can say Jack Robinson.
- 1897, Richard Marsh, The Beetle:
  And if you see a sign of anyone being about the place, — living, or dead, or anyhow — you give me a yell. I shall be on the lookout, and I’ll be with you before you can say Jack Robinson.’
- 2002, Michel Faber, The Crimson Petal and the White, Canongate Books (2010), page 772:
  Father is seated inside the carriage before you can say Jack Robinson.

Synonyms