Slăck'ness, n.

noun

n. The state of being slack; a condition opposite to tension; want of tightness or rigidity; as, the slackness of a cord or rope; remissness; negligence; inattention; as, the slackness of men in business or duty; slowness; tardiness; want of tendency; as, the slackness of flesh to heal; weakness; want of intenseness.