Sui generis
In local government, a "sui generis" entity is one that does not fit with the general scheme of local governance of a country. For example in England, the City of London and the Isles of Scilly are the two "sui generis" localities, as their forms of local government are both (for historical or geographical reasons) very different from those of elsewhere in the country. 
In a press conference during which reporters were trying to analyse his political personality, Huey Long said, "...say that I am "sui generus", and let it go at that."
Causa sui
Causa sui (, meaning "cause of itself" in Latin) denotes something which is generated within itself. This concept was central to the works of Baruch Spinoza, Sigmund Freud, Jean-Paul Sartre, and Ernest Becker, where it relates to the purpose that objects can assign to themselves. In Freud and Becker's case, the concept was often used as an immortality vessel, where something could create meaning or continue to create meaning beyond its own life.