Physiognomy is the assessment of a person's character or personality from his or her outer appearance, especially the face. The term can also refer to the general appearance of a person, object, or terrain, without reference to its implied characteristics, as in the physiognomy of a plant community.
Background
Credence of such study has varied from time to time. The practice was well accepted by the ancient Greek philosophers, but fell into disrepute in the Middle Ages when practised by vagabonds and mountebanks. It was then revived and popularised by Johann Kaspar Lavater before falling from favour again in the late 19th century. Physiognomy as understood in the past meets the contemporary definition of a pseudoscience.
No clear evidence indicates physiognomy works, though recent studies have suggested that facial appearances do "contain a kernel of truth" about a person's personality.