A more thorough explanation:

Definition: Si parcere ei sine suo periculo non potest is a Latin phrase used in Roman law. It means that if someone cannot spare another person without putting themselves in danger, they are justified in defending themselves.

Example: If someone is being attacked and cannot escape without risking harm to themselves, they are allowed to use force to defend themselves. This is an example of si parcere ei sine suo periculo non potest.

Explanation: The phrase si parcere ei sine suo periculo non potest defines the circumstances in which a defendant can plead self-defense. It means that if someone is in danger and cannot avoid it without putting themselves in harm's way, they are justified in using force to protect themselves. This principle is still used in modern law to determine whether someone acted in self-defense.