Esp. of animals: thin or feeble from inadequate feeding; lean, scrawny. Now chiefly Australian and U.S. regional.

(un-, prefix1 affix 1.)

Of an article of food: Thin, not containing much substance. Of an animal: Lean. Obsolete.

Lean, scraggy.

Originally U.S. Of an animal: adapted for or capable of ranging; having long limbs and a lean body.

Of an animal: Feeble, lacking strength or vigour.