(of a knife, etc. 刀等 having two cutting edges 雙刃的 a double-edged blade/axe/dagger 雙刃刀片/斧頭/匕首
(of a remark 說話 having two possible meanings 意義雙關的；可有兩種解釋的；模棱兩可的 having two different parts or uses, often parts that contrast with each other 有雙重效果的，有雙重作用的（常指形成鮮明對比的兩部分） the double-edged quality of life in a small town—security and boredom 小城鎮生活的雙重性——安全但乏味
Idioms
be a double-edged/two-edged sword/weapon
to be something that has both advantages and disadvantages 既有優點也有缺點；是一把雙刃劍 Fame is a double-edged sword. 名聲是一把雙刃劍。