noun
phrenologist
A person who practices phrenology, the study of skull shapes to determine character and mental faculties. This is a historical term; phrenology is now discredited.
19世紀には、骨相学者が頭蓋骨の形から性格を判断しようとした。
In the 19th century, phrenologists tried to judge character from the shape of the skull.
骨相学 is the study of phrenology itself, while 骨相学者 refers to a person who practices it.
Compound of 骨相 (こっそう, 'skull shape; phrenology') + 学者 (がくしゃ, 'scholar'). The exact historical derivation is uncertain, but the term follows a standard pattern for naming specialists in a field.