Laugh in One’s Sleeve (To)

The French is: “Rire sous cape,” or “Rire sous son bonnet.” The German is: “Ins faüstchen lachen.” The Latin is: “In stomacho ridēre.” These expressions indicate secret derision; laughing at one, not with one. But such phrases as “In sinu gaudēre” mean to feel secret joy, to rejoice in one’s heart of hearts.