巧言令色
kou.gen.rei.shoku
Literally: skill – word – command – color
Alternately: Flattery. Blandishment. Pretty words and ingratiating facial expressions, usually backed by a desire to deceive or manipulate. Making nice with someone but hiding ill intent.
Notes: This yojijukugo comes to us from the first chapter of the Analects of Confucius. It can be expanded into the saying 巧言令色少なし仁 (kougenreishoku sukunashi jin), “flattery with little benevolence,” or by extension “Those who resort to flattery often lack compassion.” Like many other compounds, this one comprises two two-character words: 巧言 denotes pretty words designed to create good feelings in the person you’re talking to; 令色 is wearing a pleasant expression.

Martin Schkreli displaying the Sociopath Smile. You know who else I’m thinking of, by this point.