What is what does yandere mean?

Yandere is a Japanese term used to describe a character, usually in anime or manga, who is obsessed with a love interest to the point of violence and sometimes even murder. The word "yandere" is a combination of 'yanderu,' which means 'mentally ill' or 'sick,' and 'dere,' which means 'affectionate' or 'lovestruck.' These characters are often portrayed as sweet and innocent at first but become possessive and dangerous if their love interest shows interest in someone else. Yandere characters can be male or female and their behavior is generally seen as disturbing and unhealthy.