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."
R v Guerin
Guerin v The Queen [1984] 2 S.C.R. 335 was a landmark Supreme Court of Canada decision on Aboriginal rights where the Court first stated that the government has a fiduciary duty towards the First Nations of Canada and established Aboriginal title to be a "sui generis" right.