riskrisk

The story

Most dictionaries consider the etymology of these Italian terms uncertain, but some suggest they perhaps come from Vulgar Latin *resecum (‘that which cuts, rock, crag’) (> Medieval Latin resicu), from Latin resecō (“cut off, loose, curtail”, verb), in the sense of that which is a danger to boating or shipping; or from Ancient Greek ῥιζικόν (rhizikón, “root, radical, hazard”).1uncertain The source flags this step as uncertain. A few dictionaries express more certainty. Collins says the Italian risco comes from Ancient Greek ῥίζα (rhíza, “cliff”) due to the hazards of sailing along rocky coasts. The American Heritage says it probably comes from Byzantine Greek ῥιζικό, ριζικό (rhizikó, rizikó, “sustenance obtained by a soldier through his own initiative, fortune”), from Arabic رِزْق (rizq, “sustenance, that which God allots”), from Classical Syriac ܪܘܙܝܩܐ ,ܪܙܩܐ (rezqā, rōzīqā, “daily ration”), from Middle Persian [script needed] (rōzīg) (whence Classical Persian روزِی (rōzī)), from Middle Persian [script needed] (rōz, “day”) (whence Classical Persian روز (rōz)), from Old Persian 𐎼𐎢𐎨𐏃 (raučah) (cognate with Sanskrit रोचस् (rocas, “light, lustre”)), from Proto-Iranian *ráwčah, from Proto-Indo-Iranian *ráwčas, ultimately from Proto-Indo-European *léwk-os, from *lewk- (‘bright; to shine’) + *-os (noun suffix).

Full etymology on Wiktionary