onychophagist
/ɒnɪˈkɒfədʒəst/(also onygophagist, onycophagist) rare
noun
A person who bites his or her nails, especially habitually or compulsively.
Origin
Mid 19th century; earliest use found in Robert Southey (1774–1843), poet and reviewer. From onycho- + -phagist.