noun
thin arm; skinny arm
Literally a thin or scrawny arm. Often used in self-deprecating or descriptive contexts.
彼女は痩せ腕を気にしている。
She is self-conscious about her thin arms.
noun
meager income; small earnings
Figurative use likening a small income to a thin arm. Slightly dated or literary, but still understood.
痩せ腕で家族を養うのは大変だ。
It's hard to support a family on a meager income.
細腕 also means 'thin arm' but is more common and neutral; 痩せ腕 emphasizes scrawniness or poverty.
Compound of 痩せ (yase, 'thin, lean') + 腕 (ude, 'arm'). The figurative sense derives from the image of a thin arm representing meager resources.