What is Right of self-defense?

The right of self-defense is the right for people to use reasonable or defensive force, for the purpose of defending one's own life or the lives of others, including – in certain circumstances – the use of deadly force.

If a defendant uses defensive force because of a threat of deadly or grievous harm by the other person, or a reasonable perception of such harm, the defendant is said to have a "perfect self-defense" justification. If defendant uses defensive force because of such a perception, and the perception is not reasonable, the defendant may have an "imperfect self-defense" as an excuse.