rackare

Etymology
From.

Noun

 * 1)  an assistant to an executioner
 * 2)  a blighter one who behaves in an objectionable or pitiable manner
 * 3)  a rascal (in a more-or-less endearing sense)
 * 4)  a devil (someone skilled)
 * 1)  a devil (someone skilled)

Usage notes
Deliberately quaint if used in an (actually) insulting sense in modern times.