Yukari is a term referring to a girl who can not be trusted when drunk. This girl will take shots until coherence is just a vague memory, BUT will never forget to remember which socially unacceptable thing to do next. She will make out with the boy you have been in love with since kindergarden with absolutely no qualms about it. She will steal your license plate or abuse the IPrelay system (internet calling system for deaf people). This type of girl should NEVER be given alcohol, be warned.
That fucking 'Yukari' drank all of my capt. Morgans and THEN I caught her trying to steal my boyfriend's pants with him still in them.