Synonyms of slacken

slacken

verb

ˈsla-kən 

1

as in to loosen

to make less taut

you'll need to slacken the rope a bit to get it free of that post

Synonyms & Similar Words

• loosen
• slack
• relax
• ease
• detach
• untie
• undo
• unfasten
• unbind
• free

Antonyms & Near Antonyms

• tension
• tighten
• tense
• stretch
• bind
• strain
• attach
• tie
• restrain
• fasten
• constrain

2

as in to slow

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

• slow
• brake
• inhibit
• decelerate
• retard
• hinder
• stop
• impede
• restrain
• halt
• obstruct
• curb
• check
• hamper
• rein
• thwart
• encumber
• set back
• constrain
• tie up
• handicap
• frustrate
• hold back
• hobble
• arrest
• sabotage
• foil
• baffle
• hold up
• bottleneck

Antonyms & Near Antonyms

• accelerate
• hasten
• hurry
• rush
• speed (up)
• encourage
• push
• urge
• step up
• quicken
• stir
• spur
• drive
• propel
• help
• facilitate
• aid
• forward
• ease
• expedite
• further
• advance
• goad
• dispatch

Synonym Chooser

How is the word slacken distinct from other similar verbs?

Some common synonyms of slacken are delay, detain, retard, and slow. While all these words mean "to cause to be late or behind in movement or progress," slacken suggests an easing up or relaxing of power or effort.

on hot days runners slacken their pace

Where would delay be a reasonable alternative to slacken?

Although the words delay and slacken have much in common, delay implies a holding back, usually by interference, from completion or arrival.

bad weather delayed our arrival

When is it sensible to use detain instead of slacken?

While in some cases nearly identical to slacken, detain implies a holding back beyond a reasonable or appointed time.

unexpected business had detained her

When would retard be a good substitute for slacken?

The synonyms retard and slacken are sometimes interchangeable, but retard suggests reduction of speed without actual stopping.

language barriers retarded their progress

How do slow and slacken relate to one another?

Both slow and slacken also imply a reduction of speed, slow often suggesting deliberate intention.

medication slowed the patient's heart rate

Example Sentences

Recent Examples of slacken

Retail sales also fell in February, while firms from Walmart to Delta Air Lines have warned of slackening demand. —Khaleda Rahman, MSNBC Newsweek, 2 Apr. 2025

There are some moments that slacken here, especially as Belflower works her way to the twist, but with no intermission, the play’s frenzied pace continues uninterrupted and helps the inevitable revelation land with a real shock. —Lovia Gyarkye, HollywoodReporter, 3 Sep. 2019

But this attempt to freeze Ukraine into submission has failed, and as spring arrives the pressure on power generation will slacken. —David Hambling, Forbes, 19 Mar. 2025

After analyzing participants’ DNA with epigenetic clocks, Bischoff-Ferrari and her colleagues found that omega-3 fatty acids actually slackened aging at the biological level, regardless of participants’ body mass index (BMI), age, and gender. —Brian Mastroianni, Health, 12 Mar. 2025