push the envelope
突破界限；挑战极限
口语·形容创新或冒险
英文释义
to go beyond the usual limits or boundaries; to take risks or be innovative in order to achieve a desired outcome
例句
The designer pushed the envelope with that futuristic dress, but everyone loved it.
典故来源
源于航空术语，指飞行员测试飞机性能极限，后泛指突破常规或挑战界限。