Loosen/ˈluːsn/ Definition 1 of 3Pro Tip 1/2Physical Adjustment Used when adjusting clothes or objects to create more space or comfort. I had to loosen my shoelaces because they were too tight. Pro Tip 2/2Object Interaction When dealing with machinery or items, 'loosen' is about turning or adjusting parts. Could you help me loosen this jar lid? It's stuck.