n. 刀口, 锐利物, 刃状物
在线英汉词典

knife-edge的短语、例句：

knife-edge n (usu sing 通常作单数) 1 cutting edge of the blade of a knife 刀刃. 2 (idm 习语) on a knife-edge (a) (of a person) nervous (about the outcome of sth) （指人）（对某事物的结果）十分焦虑
He´s on a knife-edge about his exam results. 他对考试成绩十分担心. (b) (of a situation, etc) at a critical point （指情况等）处於紧要关头
The success of the project is still very much on a knife-edge. 这一项目的成败目前仍处於关键时刻.