مَهْزُولُ الْفَصِيلِ
A person whose camel calf is lean.
Faṣīl denotes a young camel. If the owner frequently gives the she-camel's milk to guests, less milk remains for the calf, which may become thin. The calf's thinness thus conventionally points to the owner's generosity.
Like “jabān al-kalb,” this expression describes an associated effect rather than naming generosity. The literal wording and the intended allusion differ, but their relationship gives the listener a route to the implied meaning.