unwritten law
默契的规则或常识
书面/口语·描述社会默契
英文释义
a rule or expectation that is widely understood but not formally written down
例句
It's an unwritten law that you don't interrupt someone while they're speaking.
典故来源
源自社会契约概念：指虽无明文规定但被广泛遵守的行为准则，如礼仪或道德规范。