Focus on the pronunciation of slack off
English definition of “slack off”
slack off — Phrasal Verb with slack
› if someone slacks off, they stop working hard or putting effort into something: Companies just want to make sure their employees aren't slacking off. He urged Washington not to slack off in its development of new energy sources.
› if the rate of activity, development, etc. slacks off, it becomes less strong or happens less quickly: Business has slacked off so much that he spends his days remodeling the store. → Compare slacken → See also cyberslacking