骨瘦如柴

gǔshòurúchái
(idiom) as thin as a match; emaciated

CEDICT

as thin as a stick; emaciated; unhealthily skinny

Wiktionary

形容非常消瘦的样子。《儒林外史．第五回》：「后来就渐渐饮食不进，骨瘦如柴，又捨不得银子喫人参。」也作「骨瘦如豺」、「瘦骨如柴」。

重編國語辭典

Entry Composition

1 骨 gǔ bone
2 瘦 shòu
  1. thin
  2. to lose weight
  3. (of clothing) tight
  4. (of meat) lean
  5. (of land) unproductive
3 如 rú
  1. as
  2. as if
  3. such as
4 柴 chái
  1. firewood
  2. lean (of meat)
  3. thin (of a person)