c. 1825, "person in ragged clothing," from duds (q.v.). Sense extended by 1897 to "counterfeit thing," and 1908 to "useless, inefficient person or thing." This led naturally in World War I to "shell which fails to explode," and thence to "expensive failure."
例文
1. He replaced a dud valve.
彼は壊れたバルブを交換した。
2.The mine was a dud .
鉱山は廃棄された。
3.The new manager is a complete dud .
新マネージャは完全にクズです。
4.A fiery ball shot up over the rooftops，where it disappeared in mid-air--a dud .
彼は音を聞いて、発光したものが天に向かって突き進んで、屋根を突き抜けて中空で消えた。
漢英文学-家（1-26）-家（1-26）
5.The meeting was a dud as far as new business was concerned.