A tsundere is a female character in Japanese media who is portrayed as cold and aloof with an occasional warm and loving side. The character's dual personality is often used in romantic subplots, with a specific person seeing her warm side or with the tsundere character warming up over time.
"Tsundere" comes from the Japanese words "tsun tsun," meaning "to turn away," and "dere dere," meaning "lovey-dovey." The term originated in romance video games in Japan, but is also prevalent in anime, manga and entertainment venues, such as maid cafes. The term was first popularized in the visual novel "Kimi ga Nozomu Eien," an interactive novel made for the Dreamcast and PlayStation 2 game systems.