A cloud covering all of the sky from horizon to horizon.

(transitive) To cover with cloud; to overshadow; to darken.

(transitive) To make gloomy; to depress.

(transitive, bookbinding) To fasten (sheets) by overcast stitching or by folding one edge over another.

(meteorology) Covered with clouds; overshadowed; darkened; more than 90% covered by clouds.

(figuratively) In a state of depression; gloomy; melancholy.