slack

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

make less active or intense

lacking in rigor or strictness

“slack in maintaining discipline”

a cord or rope or cable that is hanging loosely

“he took up the slack”

avoid responsibilities and work, be idle

be inattentive to, or neglect

“He slacks his attention”

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

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

“slack water”

release tension on

“slack the rope”

a stretch of water without current or movement

“suddenly they were in a slack and the water was motionless”

the quality of being loose (not taut)

“he hadn't counted on the slackness of the rope”