Tsundere (ツンデレ) is a Japanese term for a character archetype which started out as internet slang from Ayashii World on August 29, 2002 to describe Ayu Daikuuji from Kimi ga Nozomu Eien, then the definition of 'tsundere' became less clear after the Tsundere Boom.

The term 'tsundere' is composed of two parts: 'tsuntsun' (ツンツン) which means 'aloof' or 'standoffish', and 'deredere' (デレデレ) which means 'flirty' or 'lovestruck'. However, the definition of 'tsundere' has become flexible since nobody has the same definitions, especially after the Tsundere Boom, so it depends on how the two parts are used. The most common definitions of a 'tsundere' character are:

1. A person who is aloof in public, but gets all flirty in private. The original definition.
2. A person who acts dignified and stuck-up in public, but gets flirty and vulnerable in private.
3. A person who is distant or pushy at first, but warms up and falls in love over time.
4. A person who normally uses rude language, but occasionally show glimpses of affection.

Some may get the idea that 'tsundere' can only be applied to female characters, which technically was true back then, but its newfound flexibility makes it possible for male and elderly characters to be classified as 'tsundere' as well. For example, some popular male 'tsundere' characters are: Yūzan Kaibara (Oishinbo), Vegeta (Dragon Ball), and Inuyasha (Inuyasha).

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Tsundere (ツンデレ), also known as Tsun (ツン) or ξﾟ⊿ﾟ)ξ, is an AA character who debut in /news4vip/ on October 12, 2005,¹⁾ just before the Tsundere Boom. She either has drill-like twintails, curly hair, or ringlets, depending on interpretation, and wears a schoolgirl outfit. In the Boon Novels, she is either depicted as Naito Horizon's girlfriend or the heroine. ξﾟ⊿ﾟ)ξ should not be confused with ξ･∀･), ζ*'ヮ')ζ, or (ﾟ⊿ﾟ).

The 'Tsundere Boom' (ツンデレブーム) was a period of time from 2005 to 2007 where it was actually once possible to see 'tsundere' addressed in real-life publications, such as:

• “Imidas 2006” (イミダス2006). November 2005, Shueisha.
• “Gendaiyōgo no Kisochishiki 2007” (現代用語の基礎知識). November 2006, Jiyu Kokuminsha.
• “Chiezou 2007” (知恵蔵2007). November 2006, Asahi Shimbun.
• “Da Vinci” (ダ・ヴィンチ). January 2007 (February 2007 issue), Media Factory.

• I just wanted to write about the AA character, but ended up being forced to write about the term.
• As a side note, the 10th episode of the Lucky Star anime, where the definition of 'tsundere' is brought up in the Lucky Channel segment, originally aired on June 10, 2007.
• The oldest 'tsundere' in anime and manga is rumored to be Hecate from Princess Knight.

• Menhera