What is the origin of 'sleep tight'?
Read moreOne of the mysteries of the English language finally explained.
Originally: pathological fear of being or becoming physically deformed. Later: specifically = "body dysmorphic disorder".
Early 20th century; earliest use found in William Dorland (1864–1956), obstetrician. From ancient Greek δύσμορϕος misshapen (from δυσ- + -μορϕος) + -phobia, after Italian dismorfofobia.