(n)the quality of being unresponsive; not reacting; as a quality of people, it is marked by a failure to respond quickly or with emotion to people or events, Syn.deadness, Ant.responsiveness
The Collaborative International Dictionary of English (GCIDE) v.0.53Collaborative International Dictionary (GCIDE)
n. The state of being destitute of life, vigor, spirit, activity, etc.; dullness; inertness; languor; coldness; vapidness; indifference; as, the deadness of a limb, a body, or a tree; the deadness of an eye; deadness of the affections; the deadness of beer or cider; deadness to the world, and the like. [ 1913 Webster ]