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."
Fourth International
In the wake of the World Congress, the line of the International Leadership was generally accepted by groups around the world, including the U.S. SWP whose leader, James P. Cannon, corresponded with the French majority to support the tactic of entrism "sui generis". At the same time, however, Cannon, Healy and Mandel were deeply concerned by Pablo's political evolution. Cannon and Healy were also alarmed by Pablo's intervention into the French section, and by suggestions that Pablo might use the International's authority in this way in other sections of the Fourth International that felt entrism "sui generis" was not a suitable tactic in their own countries. In particular, minority tendencies, exemplified in Britain by John Lawrence and in the U.S. by Bert Cochran, to support entrism "sui generis" hinted that Pablo's support for their views indicated that the International might also demand Trotskyists in those countries adopt that tactic.