‘单薄’ (dān bó) is an adjective describing something physically or metaphorically lacking substance, strength, or adequacy. The character 单 means 'single' or 'simple', suggesting simplicity or lack of layers; 薄 means 'thin' or 'shallow', reinforcing insufficiency in thickness, density, or robustness. Together, they convey a sense of frailty, slightness, or meagerness — often used for people’s physical constitution (e.g., a slender, delicate frame), sparse resources (like a thin income or scant evidence), or underdeveloped qualities (e.g., a weak argument or shallow knowledge).

This word carries a gentle, somewhat literary or descriptive tone — more common in writing and formal speech than casual conversation. It rarely implies outright weakness or failure but rather a quiet, observable lack of heft or resilience. It’s frequently applied to health-related contexts (e.g., someone recovering from illness), appearance (a slender build), or abstract concepts like support, reasoning, or data — always with a connotation of vulnerability or inadequacy that invites empathy or concern.