Definition of Jack Robinson in English:

Jack Robinson

noun

  • Only in "before one can (also could) say Jack Robinson" and variants: in a very short time; very quickly or suddenly.

Origin

Mid 18th century. From the male forename Jack + the surname Robinson, apparently as a generic personal name.

Pronunciation

Jack Robinson

/ˌdʒak ˈrɒbɪns(ə)n/