Of something luminous or illuminated: lacking in brightness or brilliancy; faint in lustre, dim.

Wanting depth or intensity; faint, weak, dim, pale. Formerly of light (archaic): in modern use, of colours, painting, or the like.

poetic. Applied to a quality of light: hazy, misty; half-lit, dim.

Of light or radiant heat, or a source of this: not bright or intense; weak, dim, reduced. Cf. burn low at burn, v.1 2c(b). Also figurative.