Home / Words / slackenNo. 0260

slacken

/ˈslækən/·verb

to become or make looser or slower; to lose tension or pace
Fig. 1 — All morning the sail is a wing — drawn full, hard-edged, the boat leaning on it while the water hisses past.
01Definition

To slacken is to let the tightness out: a rope slackens when the strain comes off, a grip slackens as attention drifts, the pace slackens on the long hill, demand slackens after the holidays. The word is built on slack — the loose length in a line that is not being pulled — so whatever slackens was, a moment ago, held taut by some effort or force. When the wind eases, the sail tells the story before the sailor feels it.

02In use
  • iAs the wind slackened, the sail sagged and the boat lost its lean.
  • iiThe runners slackened their pace on the long climb.
  • iiiDemand for heating oil slackens every year once winter ends.
03Collocations
  • the pace slackened
  • slacken your grip
  • the wind slackened
  • demand slackens
  • slacken the reins

Family slack (adjective, noun) · slackening (noun)

04Relations

=loosen, ease, relax, flag, wane

≠tighten, intensify, quicken

06TOEFL & IELTS

The tension-and-tempo verb: ropes, grips, reins, paces and demand all slacken, and in Task 1 'growth slackened' reports a slowdown without announcing a fall. The family carries the idioms: take up the slack (absorb the work others dropped), cut someone some slack (informal: judge them gently), slack off (informal: get lazy) — recognise the informal pair in listening, keep them out of essays. Against subside and abate: those calm a level or a force; slacken loosens something held taut — tension is the tell.

07Asked
What is the difference between slacken and slack off?
Register and blame. Slacken is the neutral, written verb for tension and tempo easing — the wind slackens, demand slackens, nobody is at fault. Slack off is informal and points a finger: workers who slack off have chosen laziness. A factory's output can slacken because orders fell; say its workers slacked off and you have made an accusation.
Is slacken a formal word?
Formal-leaning and mostly written — dictionaries label it 'written English', and it is a fixture of financial journalism: growth slackens, demand slackens, the pace of hiring slackens. That register is exactly why it earns marks in Task 1 trend writing, where it reports a slowdown without announcing a fall. In speech, most people just say ease off or let up.
What does 'slacken the reins' mean?
Literally, to let the horse's reins go loose so it can move as it pleases; figuratively, to relax control — a manager slackens the reins on a proven team, a state slackens the reins on the press. The grip stays on the reins: slackening is measured loosening, not letting go, which is what separates it from surrendering control outright.
Where do 'take up the slack' and 'cut someone some slack' come from?
Both from rope. Slack is the loose length in a line that is not being pulled — the folds hanging off the mast in the scene above are exactly that. Sailors take up the slack by hauling until the rope is taut again, so the phrase means absorbing what others left undone; cutting someone some slack pays out extra rope — extra room before you judge them.
What kinds of things can slacken?
Anything held taut by force or effort: ropes, sails, reins and grips literally; pace, demand, discipline and attention figuratively. The grammar runs both ways — things slacken on their own (the rain slackened around noon) and you slacken them deliberately (he slackened his grip) — with no preposition needed in either direction. 'Slacken off' adds a small informal push but changes nothing else.