yandere

Borrowed from Japanese ヤンデレ (yandere), a portmanteau of 病んでる (yanderu), contraction of 病んでいる (yandeiru), progressive tense of 病む (yamu, “to be sick”), and デレデレ (dere-dere, “to become lovey-dovey, infatuated, lovestruck”).[1][2]
Developed on the model of tsundere (“being cold and even hostile towards another person before gradually showing a warm and caring side over time”).

• IPA^(key): /ˈjɑːndɛɹeɪ/

yandere (plural yanderes)

1. (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, often homicidally so.
   • 2009 October 4, sanjian [username], “Re: Bakemonogatari - comments on the end of the TV broadcast”, in rec.arts.anime.misc, Usenet‎:

     And it finally answered the question as to whether Senjougahara is tsundere or yandere.

   • 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).

   • 2014, Olivia D. Knight, Please, Let Me Be a Seiyuu!, BookRix, →ISBN, page unnumbered:

     “Believe it, man. In fact, she's seriously creepy. Like creepier than that pink-haired girl from Future Diary.”
     “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.
2. (chiefly Japanese fiction) A character, usually a girl, who is violently obsessed with their crush.

• tsundere
• dandere
• kuudere

• deanery, renayed, year-end, yearend, yearned