Borrowing from Japanese ヤンデレ (yandere), a portmanteau of 病んでる (やんでる, yanderu), contraction of 病んでいる (やんでいる, yandeiru), progressive tense of 病む (やむ, yamu, “to be sick”), and デレデレ (dere-dere, “to become lovey-dovey, infatuated, lovestruck”).
Developed on the model of tsundere (“being cold and even hostile towards another person before gradually showing a warm and caring side over time”).
yandere (plural yandere)
- (chiefly Japanese fiction) A character, usually a girl, who fits the archetype of being genuinely kind, loving, or gentle, but suddenly switching to being aggressive or deranged.
2012, Jazmine Brusola, Rabble Rousers: A Fate/Zero Anime Review, Flyleaf (Ateneo Literary Association), page 14:
- Looking at anime charts, there's always the harem series with the dense hero and a bunch of girls whose personalities are pulled out of a set cast of tropes (the Childhood Friend, Tsundere, Yandere, and Lolita, for instance).
- “Wait, what?” Sam got that reference quickly, but was not happy with the comparison. She wasn't a psychopathic, murderous Yandere stalker, from what he could see.
- For more examples of usage of this term, see Citations:yandere.