› if business or economic activity is slack, there is less activity than usual: He wanted to sell some of his rental homes, but the region's slack economy stopped him. May was a very slack month for the entire industry. slack market/demand/salesslack time/period Summer is usually a slack time for energy demand.
› something that is slack is not strict or effective enough: Experts say that slacker financial controls may be to blame. There were claims in the media of slack corporate governance.
› someone who is slack is not working hard enough or spending enough time or care on something: Businesses that shout loudest about delayed payments are often the worst slack payers.be slack with something She's always been a bit slack with her accounts.