What does slacken mean?
To slacken is to become less tight, tense, intense, or fast, or to make something do so. The verb is especially useful for describing changes in weather, physical pressure, effort, speed, and activity: winds slacken, a grip slackens, and a schedule or pace may slacken. Its implication is usually that force or pressure is easing rather than disappearing entirely. In workplace and public contexts, 'slacken off' can mean to reduce effort or attention, often with a mildly critical tone. The word is closely related to the adjective 'slack' and is commonly used where a precise alternative such as 'weaken', 'loosen', or 'slow' might otherwise be needed.
verbTo become or cause to become less tense, tight, or firm. It can also mean to reduce the speed, intensity, or activity of something.
- To become less tense, tight, or firm.
- To reduce the speed, intensity, effort, or activity of something.
- To reduce the pressure or force exerted on something.
"The winds slackened as the storm moved away."
"Her grip on the rope gradually slackened."
"The company decided to slacken production during the holiday period."
"The storm began to slacken shortly before midnight."
To slacken is to ease the pressure—but it never means to stop caring altogether.
Reviewed by Deb Chak, Editor. AI-assisted content curated by RJS Tech Solutions LLP.
Where does slacken come from?
The word comes from the older English word 'slack', meaning loose or not firm, with the suffix '-en' added to form a verb. 'Slack' itself developed in Middle English from an Old Norse term related to 'slaka', meaning to hang loosely or let fall. The verb 'slacken' developed later by adding the verbal suffix to this older adjective, and its modern range of meanings grew to include reducing speed, pressure, and activity.
Related word forms
How slacken is actually used
Generally formal or neutral in register. It is common in contexts involving weather, tension, pressure, speed, effort, and activity. The phrase 'slacken off' is more informal and means to reduce one's effort or activity.
Easily confused with slacken
Slack is an adjective or noun meaning loose, insufficient, or lacking activity, while slacken is a verb meaning to become loose or to reduce in intensity or speed.