to (cause to) become free of ice, or to (cause to) become no longer frozen

When you get a build-up of ice in your freezer, you know it's time to defrost it. 冷冻柜出现积冰就该除霜了。

Defrost the chicken thoroughly before cooking. 鸡肉在烹饪前要彻底解冻。

Leave the chicken to defrost. 让鸡肉自行解冻。