transitive. figurative and in extended use. To overshadow, to darken; to make dull or gloomy.

transitive. To make tedious, dreary, or desolate. Cf. alange, adj.

transitive. To spoil, tarnish, or impair (something); to make less certain or optimistic; to cast a shadow over.

transitive. To cast a shadow or gloom over; to make (something) obscure, unclear or indistinct. Also: to deprive (a person) of clearness of…

transitive. figurative. To detract from the happiness or success of (an event, etc.); to cast a gloom, darkness, or unhappiness over.

To overspread with gloom, cast a shadow over, deprive of brightness; to darken with trouble.

To involve in darkness, to darken, to cloud. Also figurative, of the effect of sorrow, disappointment, etc., upon one's face, prospects, or life.

(un-, prefix2 affix 1d(b).)

figurative. To make dark, dismal, or melancholy.

transitive. To make sombre.