Refers to the psychiatric disorder characterized by an obsessive fear of gaining weight. This fear is not actually about the weight itself, rather it is tied to underlying emotional problems. Sometimes people access their self-worth in terms of body image, so in this case, thinness makes the person feel more positive about themselves and therefore they go to unhealthy links to maintain a weight that is not at all appropriate for their size.
The Mayo Clinic online has provided a large list of physical and emotional symptoms to watch for in people you think might be anorexic here: http://www.mayoclinic.com/health/anorexia/DS00606/DSECTION=symptoms
Example: After multiple relapses, she was finally able to conquer her anorexic tendencies and allow herself to eat more or less normally, thanks to the support of her family and therapist.
Fournier, G. (2010). Anorexia Nervosa. Psych Central. Retrieved on May 28, 2015, from http://psychcentral.com/encyclopedia/2008/anorexia-nervosa/