Whites/Blacks who make dating Blacks/Whites into a fetish activity. That is, they're consumed by the mythology behind a person's race (ie virility of Black men, the Black penis, Blacks as more primitive and closer to the mythical Jungle, etc.) than the person him/herself. Many are attracted to such
relationships because they perceive them as transgressive and are turned on by that.
Not all Black-White
relationships are based on Jungle Fever. However, one may be able to identify
relationships that are based on Jungle Fever by analyzing the couple's dating history. For instance, if a White person who lives in an area with few Blacks has only dated Blacks, then it's likely that that person has Jungle Fever.
Generally considered a derogatory term that hints at past colonial relationships between Blacks and Whites, where White colonizers enter, with fascination, the African Jungle in order to learn from and conquer it.