(noun, adjective, verb, adverb)


1. not tense or tight; not firmly extended.

- slack and wrinkled skin

- slack sails

- a slack rope

Similar word(s): lax, loose

2. (of water) flowing with little speed

- slack water

Similar word(s): standing

3. lacking effort or work; not using due diligence or care.

- slack in maintaining discipline

Similar word(s): negligent, lax

4. not busy; sluggish.

Sentences with slack as an adjective:

- a slack hand

- slack in duty or service

- Business is slack.


1. Slackly.

- slack dried hops


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

Definition categories: substance, debris, detritus, dust, junk, rubble

2. a noticeable deterioration in performance or quality

- a gradual slack in output

Similar word(s): falloff, slump

Definition categories: process, declension, deterioration, worsening

3. a stretch of water without current or movement

- suddenly they were in a slack and the water was motionless

Definition categories: object, stretch

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

Similar word(s): mire, morass, quag, quagmire

Definition categories: object, bog

5. the quality of being loose (not taut)

- he hadn't counted on the slackness of the rope

Similar word(s): slackness

Definition categories: attribute, looseness, play

6. a cord or rope or cable that is hanging loosely

- he took up the slack

Definition categories: man–made, cord

Sentences with slack as a noun:

- The slack of a rope or of a sail.


1. avoid responsibilities and work, be idle

Definition categories: social, fiddle, goldbrick, shirk

2. be inattentive to, or neglect

- He slacks his attention

Definition categories: cognition, neglect

3. release tension on

- slack the rope

Definition categories: change, loose, loosen

4. make less active or fast

- He slackened his pace as he got tired

Similar word(s): relax, slacken

Definition categories: change, decrease, lessen, minify

5. become slow or slower

Similar word(s): slacken, slow

Definition categories: change, weaken

6. make less active or intense

Similar word(s): abate, slake

Definition categories: change, decrease, lessen, minify

7. become less in amount or intensity

Similar word(s): abate

Definition categories: change, decrease, diminish, fall, lessen

8. cause to heat and crumble by treatment with water

- slack lime

Similar word(s): slake

Definition categories: change, hydrate

Sentences with slack as a verb:

- Lime slacks.