The expression ‘on the lam’, meaning to be a fugitive from the law, has a murky past. It is often thought to be urban slang from the 1920s used by members of the criminal underworld. The Random House Historical Dictionary of American Slang traces it back to the mid-19th century, while noting it appears related to the Old Norse word lemja, meaning ‘to depart hastily’.  Another theory traces its origins to Elizabethan England, where it meant the same thing as ‘beat it’, an idiom still in use and immortalized in a song by the late Michael Jackson.