low-cloud overcast; thick cloud cover
Meteorological term for a sky completely covered with low clouds, darker and heavier than a thin overcast. Often used in weather forecasts.
Tomorrow will be overcast with low clouds, and rain will fall from the afternoon.
Compound of 本 (hon, 'main' or 'full') and 曇り (kumori, 'cloudiness'), literally meaning 'full cloudiness'.