Nonchalantly is how you do something when you do it in that calm, “I am not bothered” way. She nonchalantly tossed the keys on the table. He nonchalantly mentioned that he had won. The -ly turns the adjective nonchalant into a word about manner: not what you are, but how you act. Same feeling as nonchalant, and the same slight risk that it sounds as if you do not care enough. It is a little more at home in writing and in storytelling than in very simple talk, where people might just say she just shrugged or he acted like it was nothing.

漫不經心地、一派輕鬆地