萎缩 (wěi suō) is a verb meaning 'to atrophy' or 'to wither' — describing a gradual decrease in size, function, or vitality of a tissue, organ, or system, often due to disease, disuse, aging, or poor nutrition. The first character 萎 (wěi) means 'to wither' or 'to wilt', evoking the image of a plant losing moisture and vigor; the second character 缩 (suō) means 'to shrink' or 'to contract'. Together, they emphasize both functional decline and physical reduction — not just becoming smaller, but losing strength or capacity.

This word is most commonly used in medical and biological contexts, such as muscle atrophy after prolonged bed rest, brain shrinkage in neurodegenerative conditions, or reduced gland activity with age. It can also appear metaphorically (e.g., 'economic萎缩') but this usage is rare and formal. Unlike general words for 'shrink' like 缩小 (suōxiǎo), 萎缩 implies pathological or degenerative change, not intentional or neutral reduction.