The word "smirk" refers to a smug, conceited, or sly smile. It often implies that the person holding the expression feels a sense of superiority, is amused at someone else's misfortune, or is being insincere. A smirk can suggest mockery or a lack of empathy towards others.
The word "smirk" originates from the late Middle English "smerke," which meant to smile. It has roots in the Old Norse word "smirkr," meaning to smile, and possibly related to the Middle Dutch "smircken," which means to smile or to smirk.