slackness

nouns

weakness characterized by a lack of vitality or energy
inanition, lassitude, lethargy, slackness
the quality of being loose (not taut)
"he hadn't counted on the slackness of the rope"
slack, slackness
is derived from
slack
the quality of being lax and neglectful
laxity, laxness, remissness, slackness
is derived from
slack