slack

slack — adjective

1. pulled or held with not enough tension; loose rather than stretched tight, so th

1.adjectiveB1
Definition

pulled or held with not enough tension; loose rather than stretched tight, so that the rope, cable, fabric, or material hangs with extra length.

Example

Anong pulled the slack rope tight again before tying it to the dock.

collocation: slack rope / slack cable

The muscles in Sofia's shoulders felt slack after the long massage.

Common collocations
  • slack rope
  • slack cable
  • go slack
  • hang slack
  • too slack
Synonyms
  • loose

    more general; describes anything not firmly fixed, not just tension

  • lax

    more formal; can mean both physically loose and lacking strictness

  • limp

    describes something that lacks stiffness or firmness, often after losing support

Antonyms
  • tight

    pulled or stretched firmly

  • taut

    stretched or pulled tight; not slack

Usage Note

Often describes physical objects such as ropes, cables, strings, belts, or fabric that should be tight but are not.

Common Mistakes

The rope is slackly.
The rope is slack.
'slack' is an adjective; use 'slackly' only as an adverb for manner of action.

2. lacking in activity or business; not showing the necessary care or effort when c

2.adjectiveB2
Definition

lacking in activity or business; not showing the necessary care or effort when carrying out a task; failing to maintain the expected standard of strictness.

Example

Business is usually slack at the cafe between lunch and dinner.

collocation: slack business / slack period

The manager warned Ryo not to get slack about cleaning the kitchen.

Common collocations
  • slack business
  • slack period
  • slack season
  • get slack about
  • go slack on
Synonyms
  • slow

    more neutral; describes low activity without implying negligence

  • lazy

    stronger negative judgement about a person's character or effort

  • negligent

    formal; failing to give proper care or attention, especially legally

  • lenient

    describes rules or punishments that are not strict enough

Antonyms
  • busy

    full of activity or customers

  • strict

    demanding that rules are followed precisely

  • diligent

    showing careful and persistent effort

Usage Note

Can describe both a business/period (not busy, slow) and a person's behaviour (not careful enough, lazy). Frequently used with 'get slack about' + noun/-ing form.

Common Mistakes

The shop is slack today' (when describing a business, this is correct).
Business is slack today.
'slack' as an adjective usually describes the business, season, or activity, not the physical shop itself.

slack — noun

slack — verb

Word family

  • slacken
    verbB2
  • slackly
    adverbB2
  • slackness
    nounB2
  • slacker
    nounB2

Synonym discussion

Sense: adjective/2

All four words describe a lack of activity, effort, or strictness, but they differ in scope and judgement. 'Slow' is the most neutral — it describes low activity or speed without blaming anyone: a shop can be slow because of the weather, not because staff are idle. 'Slack' carries mild criticism when applied to people: it suggests someone is not trying as hard as they should. 'Lazy' is a stronger personal judgement, implying a character flaw rather than a temporary lapse. 'Negligent' is formal and serious, often used in legal or professional settings to describe the failure to perform a duty with proper care. 'Lenient' shifts the focus from the person's effort to the rules or authority: a lenient teacher allows more freedom than expected. For example, a 'slow' worker might simply be learning, but a 'slack' worker is choosing not to push; a 'lazy' worker avoids effort altogether; a 'negligent' worker causes harm by not paying attention; and a 'lenient' manager permits all of this to continue.

slow ↗lazy ↗negligentlenient

Common collocations

Adverbs

  • rather slack
  • fairly slack
  • somewhat slack

Phrases

Prepositions

  • slack about
  • slack on
  • slack in

Etymology

Old EnglishProto-GermanicProto-Indo-European

The word 'slack' comes from Old English 'slæc', meaning 'loose, not tight, careless, slow'. This traces back to Proto-Germanic '*slakaz', meaning 'loose, slack', which is related to Old Norse 'slakr' and Old High German 'slah'. The Proto-Indo-European root is '*(s)leg-', meaning 'to be slack, be weak', which also gave rise to Latin 'laxus' (loose, slack) — the source of English 'lax' and 'relax'. The word has kept its core meaning of looseness and lack of tension across more than a thousand years, while also developing figurative uses about effort, activity, and strictness from as early as the 14th century. The noun sense meaning 'trousers' (slacks) appeared in the 1820s, possibly from the idea of loose-fitting clothing, and the mining term 'coal slack' dates from the 18th century.