ㄍㄨˇㄕㄡˋshòuㄖㄨˊㄔㄞˊchái

  1. 形容非常消瘦樣子儒林外史·》:後來漸漸飲食不進骨瘦如柴捨不得銀子人參。」骨瘦如豺」、瘦骨如柴」。大腹便便腸肥腦滿

as thin as a match, emaciated (idiom)​
mager (Adj)​