Tsundere (ツンデレ?, pronounced [tsɯndeɽe]) is a Japanese term for a character development process that describes a person who is initially cold and even hostile towards another person before gradually showing a warmer side over time. The word is derived from the terms tsun tsun (ツンツン?), meaning to turn away in disgust, and dere dere (デレデレ?) meaning to become 'lovey dovey'. Originally found in Japanese bishōjo games, the word is now part of the otaku moe phenomenon, reaching into other media such as maid cafes,anime, manga, novels, and even mass media. The term was made popular in the visual novel Kimi ga Nozomu Eien.
Manga author Ken Akamatsu lists tsundere as one of the special cases in his definition of moe: "The person feeling it must be stronger: The object of 'moe' is weak and dependent (like a child) on the person, or is in a situation where she cannot oppose (like a maid)... (*Tsundere only: There will be times where the stronger and weaker role is reversed)." The concept has received increasing attention in Japan, with a maid cafe named Nagomi in Akihabara started having "tsundere" events in 2006 and tsundere-themed products released (like Tomy Co.'s portable television set), and the concept increasingly reflected in recent anime, from an extended discussion of the meaning of the concept and its origin on the Internet in Lucky Star's Lucky Channel segment classifying the characters according to tsundere-ness. Another accepted definition of tsundere is a girl or a guy who has a combative attitude toward others but is also kind on the inside. They usually play out as having an attitude toward the main character, either a male or a female, and often criticizing them in one way or another, until they eventually warm up to them or fall in love with them as the series progresses, though they usually find it very hard to admit it or outright deny it in some cases.