Perhaps from Old Italian parpaglione, from Latin papilio (“butterfly”). Compare Old French paveillon, Catalan papalló, Provençal parpalhos, Lombardic parpaja. The f is difficult to account for, though it might be due to the Tuscan gorgia.
Alternatively, from the dialectal Arabic word in Maltese farfett, Tunisian Arabic فرططو (farṭaṭṭu), which is from Berber; compare Kabyle aferṭeṭṭu (“butterfly, moth”). Forms with a second -f- are apparently attested within Berber as well, but are at any rate easily explainable. For the -ll- compare the southern Italian variation between -ll and -dd- (as in Sicilian beddu versus Italian bello).
farfalla f (plural farfalle)
- bow tie
- (chiefly in the plural) pasta in the shape of butterflies or bow ties
- (swimming) the butterfly stroke
- throttle valve, butterfly valve
- farfalla in Collins Italian-English Dictionary
- farfalla in Dizionario Italiano Olivetti
- farfalla in Treccani.it – Vocabolario Treccani on line, Istituto dell'Enciclopedia Italiana
- Pianigiani, Ottorino (1907) , “farfalla”, in Vocabolario etimologico della lingua italiana (in Italian), Rome: Albrighi & Segati