slack

verb

slacked; slacking; slacks

intransitive verb

1

: to be or become slack

2

: to shirk or evade work or duty

transitive verb

1

a

: to be slack or negligent in performing or doing

b

: lessen, moderate

2

: to release tension on : loosen

3

a

: to cause to abate

b

: slake sense 3

Synonyms of slack

• loosen

Examples of slack in a Sentence

They need to stop slacking and get down to work.

the skipper ordered the crew to slack off the sheets on the mainsail

Recent Examples on the Web

Many of the buffers that once prevented small problems from becoming major failures, including spare capacity, slack inventory and human review, no longer exist because organizations have optimized for efficiency. —Aditya Vikram Kashyap, Forbes.com, 18 May 2026

Redneck points out that it's heightened the XL's front wall by 11 inches (28 cm) as compared to older Freedom models, slacking up the angle of the roof to adjust for it. —New Atlas, 13 Apr. 2026

And under Chay Yew’s somewhat slack direction, Chinese Republicans never really finds its stride. —Sara Holdren, Vulture, 27 Feb. 2026

Nitibhon, a Thai supermodel, plays her tycoon as comically drab, keeping her gaunt cheeks slack to emphasize her character’s hollowness. —Amy Nicholson, Los Angeles Times, 4 Feb. 2026

Word History

Etymology

derivative of slack entry 1

First Known Use

13th century, in the meaning defined at intransitive sense 1

Phrases Containing slack

• give/cut (someone) some slack
• pick/take up the slack
• slack-jawed
• slack off
• slack water

Rhymes for slack

• ack
• brack
• clack
• crack
• dak
• flack
• flak
• hack
• jack
• knack
• lac
• lack

Kids Definition

slack

1 of 3 adjective

ˈslak 

1

: careless sense 2

2

: not energetic

a slack pace

3

a

: not tight : not tense or taut

a slack rope

b

: lacking in firmness : weak, soft

slack control

4

: not busy

a slack season

slackly adverb

slackness noun

slack

2 of 3 verb

1

a

: to be or become slack or careless in performing or doing

b

: lessen

the wind slacked off

2

: to avoid work or duty

3

: loosen sense 2

4

a

: to cause to lessen

b

: slake sense 4

slack

3 of 3 noun

1

: a stopping of movement or flow

2

: a part of something that hangs loose without strain

take up the slack of a rope

3

plural : trousers especially for casual wear

4

: a dull season or period : lull

5

: additional tolerance or relief from pressure

cut me some slack