Pitiable means "deserving of pity," "producing compassion," or "lamentable": "These hungry children are pitiable." "The destitute family was living in a pitiable shack." Piteous refers to that which excites pity because it is suffering and miserable: "The piteous cries of the dying men echoed through the emergency room." A related word, pitiful, has the meanings of both pitiable and piteous: "a pitiful street beggar," "a pitiful exhibition."
Dictionary of problem words and expressions. Harry Shaw. 1975.