a drop-off in attendance.
a falloff in quality.
a gradual slack in output.
a slack grip.
a slack rope.
Don't relax your efforts now.
he hadn't counted on the slackness of the rope.
He slackened his pace as he got tired.
He slacks his attention.
he took up the slack.
lax in attending classes.
Production slowed.
slack and wrinkled skin.
slack in maintaining discipline.
slack lime.
slack sails.
slack the rope.
slack water.
such lax and slipshod ways are no longer acceptable.
suddenly they were in a slack and the water was motionless.
the old man's skin hung loose and grey.
The rain let up after a few hours.
The storm abated.
the team went into a slump.