The surname Adinolfi is found mainly in central-northern Italy —especially in the northwestern area—, although it also appears, more markedly, in the Neapolitan area. According to E. De Felice, it derives from the old personal name Adinolfo, documented as early as 985 in Turin in the Latinised form Atenullus, and considered a less common variant of Adolfo. It is a name of Germanic origin, introduced to Italy by the Ostrogoths and later reinforced by other Germanic peoples during the Early Middle Ages.

Along the same lines, E. Rossoni agrees that the surname comes from medieval forms such as Adinulfus or Atenulfus, composed of the Germanic elements athala ("noble, of noble lineage") and wulfa ("wolf"), meaning "noble wolf". Both authors highlight the symbolic value of the wolf in Germanic culture —associated with strength, ferocity and the god Odin—, which explains the wide diffusion of these names in warrior contexts and their subsequent transformation into a surname in Italy.