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

Contributors tried their hand at the remainder, but with so few implications left, many people drifted away; Tao’s updates slackened from their near-daily cadence to once every few weeks. — Quanta Magazine, 8 June 2026

The pace of killings slackened, with cadres told to reeducate rather than exterminate those who’d strayed. — Matthew Campbell, Bloomberg, 22 May 2026

Another factor was the slackening appeal of industrial companies, which had long absorbed the greatest number of young graduates. — Literary Hub, 15 May 2026

It’s caused when the vocal cords slacken, leading to irregular vibration and an audible cracking or rattling sound as air is released in spurts. — ArsTechnica, 14 May 2026