From the Dictionary of American Family Names:
Freni US Frequency (2010 census): 332
Italian (southern): patronymic or plural form of Freno, a nickname from Calabrian freno ‘hay’ (Italian fieno, from Latin fenum).
Some characteristic forenames: Italian: Salvatore, Rocco, Santo, Carmelo, Costantino, Domenic, Franco, Giovanna, Giuseppe, Orazio, Pina, Sante.