slackness

from WordNet (r) 3.0 (2006)

slackness
    n 1: weakness characterized by a lack of vitality or energy
         [syn: {inanition}, {lassitude}, {lethargy}, {slackness}]
    2: the quality of being loose (not taut); "he hadn't counted on
       the slackness of the rope" [syn: {slack}, {slackness}]
    3: the quality of being lax and neglectful [syn: {laxness},
       {laxity}, {remissness}, {slackness}]

from The Collaborative International Dictionary of English v.0.48

Slackness \Slack"ness\, n.
   The quality or state of being slack.
   [1913 Webster]