Underdone means the same as undercooked — food that has not been cooked enough, still raw or rare in parts that should be done. The word is most often applied to meat: an underdone roast is pink beyond the intended degree, an underdone chicken is dangerously pink at the bone. Whether underdone is a fault or a preference depends on the food — a blue steak is deliberately underdone by design, while underdone poultry is never acceptable. The term carries a note of disappointment: something promised and not delivered, the meal falling short of the cook’s intention. In professional kitchens, sending out underdone food that should be cooked through is a basic failure of craft and of food safety.