Defined by Law Grievous hurt includes:

1. Emasculation.
2. Permanent privation of sight of either eye.
3. Permanent privation of hearing of either ear.
4. Privation of any member or joint.
5. Fracture or dislocation of a bone or tooth.

When is it Justified? Only when you reasonably apprehend death, rape, or similar grievous hurt to yourself.