He loosens up by exercising.他通过运动来放松。

After a couple of drinks she had loosened up and was talking freely.喝了几杯之后她放松了下来，打开了话匣子。

He seemed nervous and his friends kept telling him to loosen up.他看起来很紧张，朋友们不停地劝他要放松。

He exercises to loosen up his muscles. [=he exercises so that his muscles are not stiff]他通过运动来放松肌肉。

I tried to loosen her up [=I tried to get her to relax and feel comfortable] by telling a few jokes.我讲了几个笑话力图让她放松。