cilice

noun2

1. •
   A garment or undergarment made of coarse cloth or animal hair worn close to the skin used by members of various Christian traditions as a self-imposed means of penance (repentance) and mortification of the flesh.

   • It was deemed meritorious to disfigure the body by neglect and filth, to extenuate it by fasting and watchfulness, to lacerate it with stripes, and to fret the wounds with cilices of horsehair. — 1824
2. •
   A leather strap studded with metallic barbs that cut into flesh as a constant reminder of Christ's suffering.