before you can say Jack Robinson
Uncertain. There is some speculation that this is a reference to Sir John Robinson, a Lieutenant at the Tower of London around 1600, 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.
- Very quickly; quicker than one expects.
- You have to be careful in that area. They'll have your wallet before you can say Jack Robinson.
- Synonym: before you can say knife