A more thorough explanation:

Battered-wife syndrome is a medical and psychological condition that affects women who have suffered physical, sexual, or emotional abuse from their spouse or partner. It is also known as battered-woman syndrome or battered-spouse syndrome.

The syndrome was first described in the 1970s by Dr. Lenore Walker. It consists of a three-stage cycle of violence:

• The tension-building stage, which may include verbal and mild physical abuse
• The acute battering stage, which includes stronger verbal abuse, increased physical violence, and perhaps rape or other sexual abuse
• The loving-contrition stage, which includes the abuser's apologies, attentiveness, kindness, and gift-giving

Battered-wife syndrome is sometimes used as a defense to justify or mitigate a woman's killing of her abuser.

For example, if a woman is being physically abused by her husband and she kills him in self-defense, she may use battered-wife syndrome as a defense in court. The defense argues that the woman was suffering from a psychological condition that made her feel trapped and helpless, and that she acted out of fear for her life.