In order to keep the original definition intact, another term has arisen to describe girls who exhibit yandere traits but do not fit the true definition of what a yanderekko entails. This term, known as yangire (ヤンギレ), refers to characters who snap suddenly out of jealousy, irritation or something similar. Yangire is a combination of the two words yanderu (病んでる), meaning to be sick, and kire or gire (切れ), meaning to cut, slice, or "to snap". This behavior is different from that of a yandere character in regard to the motivation that sparked the change in the character. The yanderekko is motivated through her love for the male protagonist, while a yangire character is motivated through other characters and will not be connected with emotions of love or attraction.
Rena Ryugu from Higurashi No Naku Koro ni is a well known yangire.
Apparently, it's a yandere without 'dere-dere' part. I.e. yangire went crazy even without love - for exemple, 'cause of some tragic events in the past
Russia (Ivan Braginsky) in Axis Powers Hetalia is typical yangire.