slacken
verb
slack·en ˈsla-kən 
slackened; slackening ˈsla-kᵊn-iŋ
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
Synonyms
- ease
- loosen
- relax
- slack
See all Synonyms & Antonyms 
Example Sentences
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.
Recent Examples on the Web The policies weaken; people lose interest in following them, spurring officials to slacken even more. 
Katherine J. Wu, The Atlantic, 16 Aug. 2022 Easterly breezes slacken through the night, mainly staying below 5 mph. A. Camden Walker, Washington Post, 13 May 2022 Winds slacken somewhat Friday night with colder lows in the upper 30s to low 40s. Washington Post, 23 Mar. 2022 Winds should begin to slacken overnight as the high pressure begins to weaken east of the Cascades. oregonlive, 28 Jan. 2022 Although the older variant is clinging on for dear life in a few pockets, its grasp will likely continue to slacken and slip under the weight of its craftier cousin. Katherine J. Wu, The Atlantic, 27 Jan. 2022 Heavy rain should slacken in the area by late morning as a warm front pushes the system north into British Columbia. oregonlive, 12 Jan. 2022 Norway’s power needs are usually largely met by a network of hydroelectric plants, but output can slacken when reservoirs run low. New York Times, 4 Jan. 2022 Tomorrow night: Skies are mainly clear, and winds should slacken compared to the day. Washington Post, 18 Dec. 2021 See More
Katherine J. Wu, The Atlantic, 16 Aug. 2022 Easterly breezes slacken through the night, mainly staying below 5 mph. A. Camden Walker, Washington Post, 13 May 2022 Winds slacken somewhat Friday night with colder lows in the upper 30s to low 40s. Washington Post, 23 Mar. 2022 Winds should begin to slacken overnight as the high pressure begins to weaken east of the Cascades. oregonlive, 28 Jan. 2022 Although the older variant is clinging on for dear life in a few pockets, its grasp will likely continue to slacken and slip under the weight of its craftier cousin. Katherine J. Wu, The Atlantic, 27 Jan. 2022 Heavy rain should slacken in the area by late morning as a warm front pushes the system north into British Columbia. oregonlive, 12 Jan. 2022 Norway’s power needs are usually largely met by a network of hydroelectric plants, but output can slacken when reservoirs run low. New York Times, 4 Jan. 2022 Tomorrow night: Skies are mainly clear, and winds should slacken compared to the day. Washington Post, 18 Dec. 2021 See More Word History
First Known Use
14th century, in the meaning defined at transitive sense 1
Kids Definition
slacken
verb
slack·en ˈsla-kən
slackened; slackening
1
: to make slower or less energetic
The wind slackened.
2
: to make less tight or firm
She slackened the reins.
slackening 1 of 2
adjective
as in softening
Synonyms & Similar Words
Relevance
- softening
- yielding
- slack
- invertebrate
- impotent
- weak
- obliging
- pliant
- complaisant
- pliable
- spineless
Antonyms & Near Antonyms
- relentless
- unrelenting
- implacable
- unyielding
- grim
- dogged
- unflinching
- determined
- persistent
- unappeasable
- tenacious
- persevering
- wilful
- stubborn
- peevish
- perverse
- obdurate
- hard
- pertinacious
- willful
- mulish
- intractable
- uncooperative
- pigheaded
- hardheaded
- headstrong
- opinionated
- self-willed
slackening
2 of 2verb
1
as in loosening
to make less taut you'll need to slacken the rope a bit to get it free of that post Synonyms & Similar Words
- loosening
- slacking
- easing
- relaxing
- undoing
- detaching
- unfastening
- untieing
- untying
- unbinding
- freeing
Antonyms & Near Antonyms
- tightening
- stretching
- straining
- binding
- attaching
- tying
- restraining
- tensing
- fastening
- tensioning
- constraining
- tieing
2
as in slowing
to cause to move or proceed at a less rapid pace drivers need to slacken their speed as they approach the sharp curve Synonyms & Similar Words
- slowing
- braking
- retarding
- decelerating
- inhibiting
- impeding
- restraining
- hindering
- stopping
- halting
- curbing
- hampering
- obstructing
- checking
- reining
- thwarting
- constraining
- encumbering
- hobbling
- handicapping
- arresting
- holding back
- sabotaging
- setting back
- tying up
- bottlenecking
- baffling
- tieing up
- foiling
- frustrating
- holding up
Antonyms & Near Antonyms
- accelerating
- hastening
- rushing
- pushing
- urging
- quickening
- driving
- speeding (up)
- encouraging
- stirring
- propelling
- stepping up
- aiding
- hurrying
- advancing
- facilitating
- spurring
- helping
- easing
- furthering
- expediting
- goading
- forwarding
- dispatching