默许 (mò xǔ) literally combines 默 (mò), meaning 'silent' or 'unspoken', and 许 (xǔ), meaning 'to permit' or 'to approve'. Together, they form a noun meaning 'tacit approval' — consent given not through words or formal agreement, but through silence, inaction, or passive acceptance. It implies that someone chooses not to object or intervene, thereby implicitly endorsing an action or situation.

This term is commonly used in social, workplace, and family contexts where explicit permission isn’t voiced but behavior signals acceptance — for example, a manager who doesn’t stop an employee from working overtime may be seen as giving 默许. It often carries subtle nuance: the approver may wish to avoid confrontation, maintain harmony, or preserve plausible deniability. Because it hinges on absence rather than affirmation, 默许 can sometimes lead to misunderstandings if intentions aren’t clarified.