朽木不雕

Explanation: Decay can not be carved wood. Metaphors do not make progress, can not become useful. 　　Usage: The main predicate; as predicate, object; containing derogatory 　　Source: "The Analects of Confucius Gongye Chang" 朽木不可雕也, not masonry wall of dirt also. " Thesaurus:  Fools grow without watering., Deadwood Difficult to carve