Anorexia: An eating disorder characterized by markedly reduced appetite or total aversion to food. Anorexia is a serious psychological disorder. It is a condition that goes well beyond out-of-control dieting. The person with anorexia, most often a girl or young woman, initially begins dieting to lose weight. Over time, the weight loss becomes a sign of mastery and control. The drive to become thinner is thought to be secondary to concerns about control and fears relating to one's body. The individual continues the endless cycle of restrictive eating, often to a point close to starvation. This becomes an obsession and is similar to an addiction to a drug. Anorexia can be life-threatening. Also called anorexia nervosa.