E. De Felice, E. Rossoni and V. Blunda agree that the surname was formed from a nickname derived from the Sicilian dialect term sciarra ("fight, quarrel, brawl, dispute"), applied to people of a quarrelsome character.

De Felice specifies that it comes from the Sicilian and in part Calabrian words sciàrra —from the Arabic šarra—, sciarrinu ("one who quarrels frequently and easily, quarrelsome") and sciarruna or sciarruni ("big fight, serious quarrel"). He notes that the variant Xarra represents the old spelling x = š.

Rossoni suggests that they would derive, directly or through hypocoristics, from the same nickname, surely attributed for the very quarrelsome character of the family line. He recalls the Roman Ghibelline prince Giacomo Colonna, nicknamed Sciarra (d. 1329), who in 1303 captured and slapped Pope Boniface VIII in Anagni. Rossoni records transformations into a surname in the Marche from the beginning of the 14th century, in Lazio in 1300, and in the L'Aquila area in the 17th century with the brigand Marco Sciarra. He further distinguishes the forms: Sciarra is typical of central Italy and of Apulia; Sciarretta is typical of Lazio, Abruzzo, Molise and the Caserta, Benevento and Naples areas.

Blunda adds that the noun designates the violent dispute in the Sicilian popular speech, frequent in the documentation of local courts.