1. to become slower, less active, or less intense
2. to make something looser or less tight
3. to become less careful or attentive in one’s efforts

Examples

• The rain began to slacken after the storm passed.
• Traffic tends to slacken during the evening hours.
• She slackened her grip on the rope.
• The coach told the team not to slacken their efforts in the final quarter.
• His pace slackened as he climbed the steep hill.
• The company’s sales slackened during the recession.
• Please slacken the tension on the guitar strings.