From Longman Dictionary of Contemporary Englishslackenslack‧en /ˈslækən/ verb [intransitive, transitive] written 1 (also slacken off)LESS to gradually become slower, weaker, less active etc, or to make something do this The heavy rain showed no signs of slackening off.slacken your pace/speed (=go or walk more slowly) Guy slackened his pace as he approached the gate.2 LOOSEto make something looser, or to become looser OPP tighten He did not let her go, but his grip on her slackened.→ See Verb table
Examples from the Corpus
slacken• The skin of her face had slackened.• Workers can be trained to do other tasks when sales slacken.• Again the firing slackens...• Support within the Labour Party for united action with the Communist Party slackened considerably after the results of the trials become known.• The company has slashed prices to fend off competitors and pump up slackening demand.• The rain slackened for a few moments, then came harder.• Rose, exhausted with running, slackened her pace a little and took in long gulps of air.• Don't allow the reins to slacken, keep them taut.• Slacken off the line, and pull the fishing rod towards you.• I pointed out that by slackening our programme efforts we would simply court mediocrity.• She would not even slacken speed as she raced through the far-ranging Jovian satellite system.• The boat surged forwards as he slackened the rope.• But it should slacken when the leash is held normally.From Longman Business Dictionaryslackenslack‧en /ˈslækən/ (also slacken off) verb [intransitive, transitive] to gradually become weaker or less active, or to make something do thisAs business slackens, accounting firms are reducing their professional staffs and shaking up office leadership.Industrialdemand hasslackened off because of the worldwide economic slowdown.The ending of a special tax incentive is widely expected toslacken the pace of new car purchases. —slackening noun [uncountable]The price cuts may help exporters get through the usual seasonalslackening of oildemand in the second quarter.→ See Verb table 