What is the meaning of slackening?

noun

• An occurrence of control or strength weakening.
  • usage: "the relaxation of requirements"; "the loosening of his grip"; "the slackening of the wind"
  • synonyms: relaxation, loosening

verb

• Become slow or slower.
  • usage: "Production slowed"
  • synonyms: slow, slow down, slow up, slack, slacken
• Make less active or fast.
  • usage: "He slackened his pace as he got tired"; "Don't relax your efforts now"
  • synonyms: slack, slacken, slack up, relax
• Become looser or slack.
  • usage: "the rope slackened"
  • synonyms: slacken
• Make slack as by lessening tension or firmness.
  • synonyms: slacken, remit