From a nickname for a strong person, from  robusto "strong", from Latin robustus "firm, solid, oaken".0

The authors agree that this surname derives probably from nicknames referring to the physical build of the first bearer, or else from medieval names such as Robusto or Robustino.

E. Rossoni notes that the surname is very diffused in Sarno, in the Salerno area, with a presence also in Grosotto, in the Sondrio area. He further mentions the variants Robusti, proper to the Cremona area, and Robustini, of the Ferrara area. Among the historical figures linked to these forms, he recalls the Venetian painter Iacopo Robusti, known as Tintoretto (1518–1594), and Giacomo Robustelli, leader of the Catholic revolt of the Valtellina begun in Tirano in 1620, known as the Sacro Macello.

F. Miranda broadens the geographic distribution: besides the Sarno area, he indicates a presence in Lombardy, especially in the Brescia, Como and Milan areas, and with a smaller concentration in Lazio, Piedmont, Tuscany and Emilia-Romagna. In Sicily, he documents it in the Catania area —in Aci Castello and Motta Sant'Anastasia—, in the Palermo area and in the Enna area, in particular in Regalbuto.