违背 is a formal, two-character verb meaning 'to go against', 'to violate', or 'to betray' — typically referring to principles, promises, laws, expectations, or moral standards. The first character 违 (wéi) means 'to violate' or 'to disobey', while the second character 背 (bèi) means 'to turn one's back on' or 'to abandon'. Together, they form a compound emphasizing deliberate rejection or failure to uphold something important.

This word carries a strong negative connotation and is commonly used in written Chinese, official statements, ethical discussions, or serious interpersonal contexts — for example, when someone breaks a promise, ignores rules, or acts contrary to social norms or personal values. It’s rarely used in casual speech and almost never with physical objects; instead, it always governs an abstract noun like 原则 (principle), 承诺 (promise), 道德 (morality), or 期望 (expectation).