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


ease, loosen, relax, slack


strain, stretch, tense, tension, tighten

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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

Our internal taskmasters, who admonish us to work harder and never slacken the pace, are powerful. Cassie Werber, Quartz at Work, "There’s a mindfulness exercise that the strongest leaders need to try," 31 July 2019 Skies stay mostly clear and northwesterly winds slacken off to about 5 mph. Rick Grow, Washington Post, "D.C.-area forecast: Typical summer heat and humidity reign today through the weekend," 12 July 2019 As slackening global demand crimps purchases of Chinese exports, for instance, the trade-off between domestic deleveraging and robust growth in Beijing becomes much starker. The Economist, "The global economy is on a knife-edge," 27 June 2019 That has generated grumbling among some within the academy’s ranks who feel that standards have been slackened in the effort to boost inclusion. Josh Rottenberg,, "Film academy invites more women than men to key director, writer and producer branches," 1 July 2019 If the economy slows, Amherst could benefit in two ways: Home prices would slacken, creating buying opportunities for investors, and rental demand would rise. Shawn Tully, Fortune, "Meet the A.I. Landlord That’s Building a Single-Family-Home Empire," 21 June 2019 Pilots who pull back forcefully on the column — sometimes called the stick — might suddenly feel a slackening of resistance. Anchorage Daily News, "The inside story of MCAS: How Boeing’s 737 MAX system gained power and lost safeguards," 13 Mar. 2019 The demand for Cambodia’s sand certainly won’t slacken any time soon. Vince Beiser, National Geographic, "Sand mining threatens ways of life, from Cambodia to Nigeria," 23 Apr. 2019 This year could be different, after economic growth in 2018 slackened to its slowest pace since 1990 and annual auto sales fell for the first time since that same year. Kevin Kingsbury, WSJ, "China’s Slowdown Is a Drag for Fuel Refiners," 23 Jan. 2019

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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Statistics for slacken

Last Updated

20 Aug 2019

Look-up Popularity

Time Traveler for slacken

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

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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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More from Merriam-Webster on slacken

Rhyming Dictionary: Words that rhyme with slacken

Thesaurus: All synonyms and antonyms for slacken

Spanish Central: Translation of slacken

Nglish: Translation of slacken for Spanish Speakers

Britannica English: Translation of slacken for Arabic Speakers

Comments on slacken

What made you want to look up slacken? Please tell us where you read or heard it (including the quote, if possible).


not constant or steady

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