Earlier form might have been *fnyj, before *pnyj, from Proto-Albanian*pnewa hence from Proto-Indo-European*pnew-. Compare πνέω(pnéō, “I blow”). A similar development "p-" > "f-" happened to the word ftoh from Old Albanian ptoh. Alternatively from Proto-Albanian*spHṛū-, from Proto-Indo-European*(s)peys- 'to blow, breathe'.