Self defense

Self-defense (or self-defence; see spelling differences) is the act of defending oneself, one's property or the well-being of another from physical harm and violence. The use of the right of self-defense as a legal justification for the use of force in times of danger is available in many jurisdictions, but the interpretation varies widely. To be acquitted of any kind of physical harm-related crime (such as assault and battery and homicide) using the self-defense justification, one must prove legal provocation, meaning that one must prove that they were in a position where not using self-defense would most likely lead to significant injury to life, limb, or property.

In politics, the concept of national or mutual self-defense to counter a war of aggression refers to a defensive war organized by the state and is one possible criterion in the just war theory.

Unarmed
Many styles of martial arts are practiced for self-defence or include self-defence techniques. Some styles train primarily for self-defence, while other martial/Combat sports can be effectively applied for self-defence. To provide more practical self-defence, many modern day martial arts schools now use a combination of martial arts styles and techniques, and will often customize self-defence training to suit the participants' lifestyles, occupations, age groups and gender. The practice of combining martial arts styles for competitive sport is most often referred to as Mixed Martial Arts or MMA.

Armed

 * See also: Castle Doctrine
 * See also: Less-lethal weapon

In some countries, it is legal to use or carry weapons (for example knives, firearms or batons) for purposes of self-defense. In other countries, this may be illegal or may require a license, or some items may be legal to carry without a license, while others, most commonly firearms, are not. Limitations on the use of weapons for personal defense are a source of controversy in some countries, pitting self-defense rights against efforts to combat violent crime via restricting access to common weapons.

Everyday objects, such as baseball bats or aerosol spray cans, can also be used as improvised weapons for self-defense, but are not likely to be as effective as purpose built weapons. Some non-lethal weapons as the Kubotan have also been built to resemble everyday objects, such as keychains.

Pepper spray and personal stun guns are common less-lethal self defense alternatives. Pepper sprays can have a range between 5-20 feet, and act by delivering a spray or foam containing highly irritating chemicals. Handheld stun guns operate by delivering an incapacitating electric shock, and must actually come in contact with the assailant to be effective, with the exception of tasers which use gas-propelled barbs connected to the taser by conductive wire to deliver the shock.

De-escalation
De-escalation is the use of voice, tone, and body language to calm a potentially violent situation before violence actually ensues. Terms such as 'verbal judo' are used in reference to de-escalation, because the verbal tactics are similar to the physical tactics in the martial art of judo.

Avoidance
Being aware of and avoiding potentially dangerous situations is a method of self-defense. Leaving the situation where possible is often considered to be safer than attempting physical contact with an attacker. Due to its non-physical nature, awareness and flight are emphasized in women's self defense classes where it is assumed that the attacker would be larger and stronger than the victim.

Personal alarms
Personal alarms are a way to practice passive self-defense. A personal alarm is a small, hand-held device that emits strong, loud, high pitched sounds to deter attackers because the noise will draw the attention of passersby, they may also be used as sonic weapons to distract an attacker. Child alarms often function as locators or device alarms such as triggering an alert when a swimming pool is in use to help prevent dangerous situations in addition to being a deterrent against would-be aggressors.