A devilish grin is a facial expression that conveys mischievousness, amusement, or even malice. It is often characterized by a SMIRK or SNEER. A SMIRK is a slight, knowing smile that often implies smugness or self-satisfaction. A SNEER is a facial expression of contempt or scorn, usually characterized by a curled lip and a scornful look. Both expressions are often used to convey a sense of superiority or disdain.