E. Rossoni notes that this surname is typical of the Trapani area —specifically of Trapani, Erice and Paceco— and derives from the personal name Guaranus, documented in a deed of 1210 in Messina, Sicily.

V. Blunda supplies a more detailed etymological perspective: he considers the surname to be of Germanic root and to derive from the personal name Warane, linked to the root wara, meaning "attention, care, protective watchfulness". This root gave rise to the Italian verb guardare and the Spanish guardar, preserving the original sense of custody directed towards a person or object. Blunda adds that in Lombard legal culture the protective function was a central institution: the head of the household exercised mundium over the women and minors of the domestic group, and the prestige of the lineage depended on that capacity.