My Italian name dictionary (
Santi e Fanti by
Enzo La
Stella T.) says that Svevo/Sveva was originally an ethnic name for someone from Svevia, the Italian name for the region of Germany which is called Swabia in English.
http://en.wikipedia.org/wiki/Swabia
La
Stella goes on to say that one of the first examples of the male form Svevo was its use in the pen name
Italo Svevo, by the author whose real name was
Ettore Schmitz (1861-1928). He then mentions its use for a feminine pen name; the authors Nullo and
Bice Cantaroni wrote novels which were bestsellers in Italy in the 1990s under the pen name Sveva Casati Modigliani.