Definition of "Slack" :

noun: a cord or rope or cable that is hanging loosely

"He took up the slack."

noun: the quality of being loose (not taut)

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

noun: a soft wet area of low-lying land that sinks underfoot

noun: a stretch of water without current or movement

"Suddenly they were in a slack and the water was motionless."

noun: a noticeable deterioration in performance or quality

"A gradual slack in output."

noun: dust consisting of a mixture of small coal fragments and coal dust and dirt that sifts out when coal is passed over a sieve

verb: cause to heat and crumble by treatment with water

"Slack lime."

verb: become less in amount or intensity

verb: make less active or intense

verb: become slow or slower

verb: make less active or fast

"He slackened his pace as he got tired."

verb: release tension on

"Slack the rope."

verb: be inattentive to, or neglect

"He slacks his attention."

verb: avoid responsibilities and work, be idle

adjective: lacking in rigor or strictness

"Slack in maintaining discipline."

adjective: flowing with little speed as e.g. at the turning of the tide

"Slack water."

adjective: not tense or taut

"Slack and wrinkled skin."