Open English Wordnet
Nouns
(n)slackdust consisting of a mixture of small coal fragments and coal dust and dirt that sifts out when coal is passed over a sieve (n)slump, slack, drop-off, falloff, falling offa noticeable deterioration in performance or quality“the team went into a slump”,
“a gradual slack in output”,
“a drop-off in attendance”,
“a falloff in quality” (n)slack, slack watera stretch of water without current or movement“suddenly they were in a slack and the water was motionless” (n)slack, slacknessthe quality of being loose (not taut)“he hadn't counted on the slackness of the rope” (n)slacka cord or rope or cable that is hanging loosely“he took up the slack” Verbs
(v)slackavoid responsibilities and work, be idle (v)slackbe inattentive to, or neglect“He slacks his attention” (v)slackrelease tension on“slack the rope” (v)slack, slacken, slack up, relaxmake less active or fast“He slackened his pace as he got tired”,
“Don't relax your efforts now” (v)slack, slakecause to heat and crumble by treatment with water“slack lime” Adjectives
(s)loose, slacknot tense or taut“the old man's skin hung loose and grey”,
“slack and wrinkled skin”,
“slack sails”,
“a slack rope”,
“a slack grip” (s)slackflowing with little speed as e.g. at the turning of the tide“slack water” (s)lax, slacklacking in rigor or strictness“such lax and slipshod ways are no longer acceptable”,
“lax in attending classes”,
“slack in maintaining discipline”