E. Rossoni proposes that this surname would have been given to foundling children, in reference to the dialect term gnudi ("naked"), that is, deprived of everything. According to Rossoni, the surname is fairly widespread in Emilia-Romagna, especially in Bologna and nearby localities such as Zola Predosa, Calderara di Reno and Baricella, as well as in Modena, Ferrara and Portomaggiore. He also records a small presence in Cascina, in the Pisa area. He further mentions the variant Ignudi, very rare, which would appear to be likewise proper to the Pisa area.

F. De Laurentiis holds a different hypothesis: he considers the surname to be an abbreviation of Benvenuti, from which it would take its meaning, and places it as typical of Emilia-Romagna and Lombardy.