肃穆 (sù mù) is an adjective describing a solemn, reverent, and deeply respectful atmosphere—often hushed, dignified, and emotionally restrained. The character 肃 means 'solemn' or 'stern', conveying seriousness and discipline; 穆 means 'reverent', 'quiet', or 'profound', evoking inner stillness and awe. Together, they form a compound that emphasizes both outward decorum and inward reverence, commonly used to describe settings like memorial halls, temples, funerals, or quiet natural scenes imbued with gravity.

This word is frequently applied to physical environments or collective moods rather than individuals alone—it describes how a space or gathering feels, not how a person behaves. It carries a formal, literary register and appears often in written Chinese, news reports about ceremonies, and descriptions of historical or spiritual sites. Unlike casual words for 'serious', 肃穆 implies deep respect rooted in tradition, loss, or sacredness—not mere gravity or concentration.