slack·​en | \ ˈsla-kən How to pronounce slacken (audio) \
slackened; slackening\ ˈsla-​kᵊn-​iŋ How to pronounce slacken (audio) \

Definition of slacken

transitive verb

1 : to make less active : slow up slacken speed at a crossing
2 : to make slack (as by lessening tension or firmness) slacken sail

intransitive verb

1 : to become slack or slow or negligent : slow down
2 : to become less active : slack

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Synonyms & Antonyms for slacken



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Choose the Right Synonym for slacken

delay, retard, slow, slacken, detain mean to cause to be late or behind in movement or progress. delay implies a holding back, usually by interference, from completion or arrival. bad weather delayed our arrival retard suggests reduction of speed without actual stopping. language barriers retarded their progress slow and slacken also imply a reduction of speed, slow often suggesting deliberate intention medication slowed the patient's heart rate , slacken an easing up or relaxing of power or effort. on hot days runners slacken their pace detain implies a holding back beyond a reasonable or appointed time. unexpected business had detained her

Examples of slacken in a Sentence

Sales show no sign of slackening. As he began to relax, his grip on the steering wheel slackened. The captain ordered us to slacken the sails.
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Recent Examples on the Web Through tonight: Winds will slacken a good deal in the evening and become relatively light overnight. Washington Post, "PM Update: Winds ease tonight, but they’ll pick back up Wednesday," 23 Feb. 2021 At some point, consumer demand will slacken, manufacturers’ production will rise to meet the market, and there will be an equilibrium, however short-lived. Andrew Mckean, Outdoor Life, "Is the Military Really Buying Up All the Civilian Ammo?," 5 Mar. 2021 Still, there's a tactile thrill to his visual set pieces (the custom gowns by Prada are deliriously gorgeous) and a headlong propulsion to the story that only begins to slacken in the film's rickety final third. Leah Greenblatt,, "United States vs. Billie Holiday," 19 Feb. 2021 Westerly winds slowly slacken somewhat, but early gusts around 25 mph are still possible. Washington Post, "D.C.-area forecast: Snow showers could whiten the ground in spots today, with wind chills through tomorrow," 25 Dec. 2020 Recently, scientists released new observations about aging black holes, a special case in which the black holes appear to slacken and begin belching information back over the event horizon. Caroline Delbert, Popular Mechanics, "New Experiment Utterly Alters What We Know About Black Holes," 14 Dec. 2020 Tonight: Skies generally clear out and northerly breezes slacken slowly but surely through the evening hours. A. Camden Walker, Washington Post, "D.C.-area forecast: Raindrops end this morning, then it gradually clears with breezy conditions," 30 Oct. 2020 But the rate of decline slackened as some parts of the economy were allowed to reopen. Julia Horowitz, CNN, "Was April rock bottom for the economy? New data provides some clues," 21 May 2020 Some of these have been famous for grace and elegance, others more infamous for what could be termed jaw-slackening design. Mike Duff, Car and Driver, "Aston Martin Vantage Zagato V12 Coupe, Speedster Pair Revealed," 21 Apr. 2020

These example sentences are selected automatically from various online news sources to reflect current usage of the word 'slacken.' Views expressed in the examples do not represent the opinion of Merriam-Webster or its editors. Send us feedback.

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First Known Use of slacken

14th century, in the meaning defined at transitive sense 1

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Time Traveler for slacken

Time Traveler

The first known use of slacken was in the 14th century

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Statistics for slacken

Last Updated

31 Mar 2021

Cite this Entry

“Slacken.” Dictionary, Merriam-Webster, Accessed 21 Apr. 2021.

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More Definitions for slacken



English Language Learners Definition of slacken

: to become slower or less active : to slow down
: to make (something) slower or less active
: to become less tight or to make (something) less tight


slack·​en | \ ˈsla-kən How to pronounce slacken (audio) \
slackened; slackening

Kids Definition of slacken

1 : to make slower or less energetic The wind slackened.
2 : to make less tight or firm She slackened the reins.

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Comments on slacken

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