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."
Status in Roman legal system
"Status familiae" is the legal status of an individual in the family. The pater familias had the authority in the family (patria potestas), and everyone was subjected to him based on adgnatio (kinship only from father's side). This had an impact in private law. There is a distinction between alieni iuris (persons under patria potestas) and sui iuris (persons autonomous of patria potestas, who could only be the pater familias himself).
Filius familias had ius suffragii and ius honorum, but in the area of private law he was restricted because of patria potestas.