Koitsu

コイツ (koitsu) literally means "this one" and is used to refer to a person or thing near the speaker, or someone being talked about. It comes across as blunt or rough — it can express contempt or hostility toward someone, but it can also be used casually between close friends who are comfortable being direct with each other. It can even refer to objects or animals (e.g. "this thing won't move"). Never use it toward superiors, elders, or in any formal setting — it will come across as extremely disrespectful.