1.Definition: the quality of being lax and neglectful

Related Noun(s):laxity, laxness, remissness

Category: General

2.Definition: the quality of being loose (not taut)

"He hadn't counted on the slackness of the rope"

Related Noun(s):slack

Category: General

3.Definition: weakness characterized by a lack of vitality or energy

Related Noun(s):inanition, lassitude, lethargy

Category: General