Insensible; unfeeling.
Not bright or intelligent; stupid; having slow understanding.
Not intense; felt indistinctly or only slightly.
Sluggish, listless.
Boring; not exciting or interesting.
Not shiny; having a matte finish or no particular luster or brightness.
Lacking the ability to cut easily; not sharp.
Cloudy, overcast.
Heavy; lifeless; inert.
Not clear, muffled.
To render dull; to remove or blunt an edge or something that was sharp.
To soften, moderate or blunt; to make dull, stupid, or sluggish; to stupefy.
To lose a sharp edge; to become dull.
To render dim or obscure; to sully; to tarnish.
Insidious.
Tenuous; rarefied; of low density or thin consistency.
Barely noticeable, not obvious, indistinct.
Cleverly contrived.
Cunning, skillful.
Hard to grasp; not obvious or easily understood.