An onychophagist is a person who has the compulsive habit of nail biting. The word is derived from the Greek ‘onux’ - claw / nail and ‘phagos’ - eater.

There may be a genetic link to onychophagia; some people appear to have an inherited tendency toward developing body-focussed repetitive behaviours, as well as higher-than-average rates of mood and anxiety disorders in immediate family members. Nail biting is associated with anxiety, because the act of chewing on nails reportedly relieves stress, tension, or boredom.

More Info: www.psychologytoday.com