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."
Suum cuique
The Latin phrase relates to an old Greek principle of justice which translates literally into English as "to each his own". Plato, in "Republic", offers the provisional definition that "justice is when everyone minds his own business, and refrains from meddling in others' affairs" (Greek: "...τὸ τὰ αὑτοῦ πράττειν καὶ μὴ πολυπραγμονεῖν δικαιοσύνη ἐστί...", 4.433a). Everyone should do according to his abilities and capabilities, to serve the country and the society as a whole. Also, everyone should receive "his own" (e.g., rights) and not be deprived of "his own" (e.g., property) (433e).