A term expresses a thick concept if it expresses a specific evaluative concept that is also substantially descriptive. It is a matter of debate how this rough account should be unpacked, but examples can help to convey the basic idea. Thick concepts are often illustrated with virtue concepts like courageous and generous, action concepts like murder and betray, epistemic concepts like dogmatic and wise, and aesthetic concepts like gaudy and brilliant. These concepts seem to be evaluative, unlike purely descriptive concepts such as red and water. But they also seem different from general evaluative concepts. In particular, thick concepts are typically contrasted with thin concepts like good, wrong, permissible, and ought, which are general ev...