adverb
With insufficient light for easy discernment or comprehension.
With a dark appearance.
(figuratively) In a manner which is not readily visible or noticeable; inconspicuously.
(figuratively) In a manner which retards or prevents discernment; clandestinely.
(figuratively) In a manner which is difficult to understand, or which retards or prevents understanding; incomprehensibly.
(figuratively) In a manner which tends to produce uncertainty or confusion; bewilderingly.
(figuratively) In a manner which produces an inward conviction of future misfortune; ominously.
(figuratively) In a morbid manner; morbidly, sinisterly.
adjective
(chiefly poetic) Relating to darkness or obscurity.