The Chinese idiom **闷闷不乐** (mèn mèn bù lè) is formed through a descriptive and accumulative structure: the character **闷** means "depressed" or "stifled," and its reduplication **闷闷** intensifies this feeling to a state of being deeply sullen or gloomy; this is then directly combined with the negative phrase **不乐** ("not happy"), so the entire compound literally and figuratively depicts a persistent, brooding unhappiness where one is weighed down by gloom and unable to be cheerful.