knife-edge
/ˈnaɪfedʒ/noun
1- the edge of a knife刀刃。
1.1
- as modifier(of creases or pleats in a garment) very fine（衣服的折痕或褶皱）精细的。
1.2
- in sing. a tense situation, especially one finely balanced between success and failure紧张的形势, 千钧一发的状态：
they have been living on a knife-edge since his libel action.
自从他提出诽谤起诉以来, 他们一直生活在紧张的形势之中。
1.3
- a steel wedge on which a pendulum or other device oscillates or is balanced（支撑钟摆等装置以使其来回摇摆或保持平衡的）刃形支承。
1.4
- a narrow, sharp ridge; an arête陡峭的山脊, 刃岭。