1. the quality or state of being loose, not tight, or not taut
2. lack of effort, care, or diligence; negligence
3. reduced activity or intensity; sluggishness

Examples

• The slackness of the rope made it difficult to climb.
• His slackness in completing assignments hurt his grades.
• The teacher criticized the student’s slackness in studying.
• There was noticeable slackness in the cable that needed tightening.
• The company’s slackness in quality control led to product recalls.
• Economic slackness resulted in fewer job opportunities.
• The slackness of her grip caused her to drop the ball.