好运 (hǎo yùn) is a noun meaning 'good luck', commonly used in wishes (祝你好运). It contrasts with 运气 (yùn qi), which is a neutral noun for 'luck' (good or bad) and often paired with 好/坏. 幸运 (xìng yùn) is an adjective/noun describing a person or event as 'fortunate', while 福 (fú) and 福气 (fú qi) refer to lasting blessings or happiness, often from fate or merit.