WordNet (r) 3.0 (2006):

unresponsiveness
    n 1: 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; "she began to
         recover from her numb unresponsiveness after the accident";
         "in an instant all the deadness and withdrawal were wiped
         away" [syn: unresponsiveness, deadness] [ant:
         responsiveness]