败兴 (bài xìng) literally means 'to ruin enthusiasm' — the character 败 (bài) means 'to fail, spoil, or ruin', and 兴 (xìng) means 'enthusiasm, excitement, or joy'. Together, they form a verb describing the act of dampening someone’s mood or spoiling their anticipation or pleasure, often unexpectedly or due to external circumstances. It is commonly used when plans go awry, expectations are unmet, or an otherwise delightful experience is marred by something disappointing.

This word carries a mild-to-moderate negative tone and is frequently used in spoken and written Chinese to express empathetic disappointment — for instance, when rain cancels an outdoor picnic, or a key person fails to show up at an event. It focuses on the emotional impact rather than assigning blame, and is typically used reflexively or with a third-person subject (e.g., ‘这真败兴’ — 'This is really a mood-killer').