godan verb (-ru), intransitive verb
become emaciated; waste away; get very thin
Describes a person or animal becoming extremely thin, often due to illness, hardship, or neglect. Stronger than 痩せる; implies a pitiful or alarming state.
長い闘病生活で彼はすっかり痩せ細ってしまった。
He became completely emaciated after a long illness.
捨てられた子猫は痩せ細り、今にも死にそうだった。
The abandoned kitten was so emaciated it looked like it might die at any moment.