A person who practices physiognomy, the art of judging character from facial features. This is a specific, somewhat technical term; the practice itself is called 人相学 (にんそうがく) or 人相術 (にんそうじゅつ).
As a physiognomist, he guesses people's personalities from their facial features.
Compound of 人相 (にんそう, 'physiognomy') + 見 (み, 'seeing, judging'). The reading み is the continuative form of 見る (みる).