| Noun | 1. | slack - dust consisting of a mixture of small coal fragments and coal dust and dirt that sifts out when coal is passed over a sieve | |
| 2. | slack - a 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" | |
| 3. | slack - a stretch of water without current or movement; "suddenly they were in slack water"stretch - a large and unbroken expanse or distance; "a stretch of highway"; "a stretch of clear water" | |
| 4. | slack - the condition of being loose (not taut); "he hadn't counted on the slackness of the rope"looseness, play - movement or space for movement; "there was too much play in the steering wheel" | |
| 5. | slack - a cord or rope or cable that is hanging loosely; "he took up the slack"cord - a line made of twisted fibers or threads; "the bundle was tied with a cord" | |
| Verb | 1. | slack - avoid responsibilities and work, be idle | |
| 2. | slack - be inattentive to, or neglect; "He slacks his attention"neglect - fail to attend to; "he neglects his children" | |
| 3. | slack - release tension on; "slack the rope"loosen, loose - make loose or looser; "loosen the tension on a rope" | |
| 4. | slack - make less active or fast; "He slackened his pace as he got tired"; "Don't relax your efforts now" | |
| 5. | slack - become slow or slower; "Production slowed"weaken - become weaker; "The prisoner's resistance weakened after seven days" | |
| 6. | slack - make less active or intense | |
| 7. | slack - become less in amount or intensity; "The storm abated"; "The rain let up after a few hours"decrease, diminish, lessen, fall - decrease in size, extent, or range; "The amount of homework decreased towards the end of the semester"; "The cabin pressure fell dramatically"; "her weight fall to under a hundred pounds"; "his voice fell to a whisper" | |
| 8. | slack - cause to heat and crumble by treatment with water; "slack lime"hydrate - cause to be hydrated; add water or moisture to; "hydrate your skin" air-slake - alter by exposure to air with conversion at least in part to a carbonate; "air-slake lime" | |
| Adj. | 1. | slack - not tense or taut; "the old man's skin hung loose and gray"; "slack and wrinkled skin"; "slack sails"; "a slack rope"lax - not taut or rigid; not stretched or held tight; "a lax rope" | |
| 2. | slack - lacking in strength or firmness or resilience; "flaccid muscles"; "took his lax hand in hers"; "gave a limp handshake"; "a limp gesture as if waving away all desire to know" G.K.Chesterton; "a slack grip"weak - having little physical or spiritual strength; "a weak radio signal"; "a weak link" | |
| 3. | slack - flowing with little speed as e.g. at the turning of the tide; "slack water"standing - (of fluids) not moving or flowing; "mosquitoes breed in standing water" | |
| 4. | slack - lacking in rigor or strictness; "such lax and slipshod ways are no longer acceptable"; "lax in attending classes"; "slack in maintaining discipline"negligent - characterized by neglect and undue lack of concern; "negligent parents"; "negligent of detail"; "negligent in his correspondence" | |