Baretti: A dictionary of the English and Italian languages
Fósc-o, adj.
1. brown, tawney, dun, or dark colour; 2. dusky, cloudy, dark. Aria fosca,cloudy, dark, overcast air or atmosphere. Tempo —, cloudy weather; 3. sad, sorrowful, melancholy, unhappy; adv. Fósc-aménte.
Florio: a worlde of wordes, or most copious, dictionarie in Italian and English