(of a knife, etc. 刀等 having two cutting edges 双刃的 a double-edged blade/axe/dagger 双刃刀片/斧头/匕首
(of a remark 说话 having two possible meanings 意义双关的；可有两种解释的；模棱两可的 having two different parts or uses, often parts that contrast with each other 有双重效果的，有双重作用的（常指形成鲜明对比的两部分） the double-edged quality of life in a small town—security and boredom 小城镇生活的双重性——安全但乏味
Idioms
be a double-edged/two-edged sword/weapon
to be something that has both advantages and disadvantages 既有优点也有缺点；是一把双刃剑 Fame is a double-edged sword. 名声是一把双刃剑。