Sui generis
Sui generis (; ) is a Latin phrase that means "of its (his, her, their) own kind; in a class by itself; unique."
Sui iuris
In civil law, the phrase sui juris indicates legal competence — the capacity to manage one's own affairs (Black's Law Dictionary, Oxford English Dictionary) — as opposed to alieni juris, which means someone under the control of another (such as a child or mentally incapable person might be). It also indicates an entity capable of suing and/or being sued in a legal proceeding in their own name (in personam) without the need of an ad litem. (A court appointed representative, acting on behalf of a defendant, that is deemed to be incapable of representing themselves).