adjective
Production has fallen off because the workers are getting slack
The flag hung down, slack in the still air
verb
Don't let the foreman find you slacking
Often, slack or slacken off or up
Slack off the stern line a bit
Barnes could not keep up his terrific pace and is beginning to slack off. Business has slackened off since Christmas
noun
How do you compensate for the slack in sales of ski equipment during the summer?
There's too much slack in that mooring line
US