名詞 dud:

1. someone who is unsuccessful
   同義詞：flop, washout
2. an explosion that fails to occur
   同義詞：misfire
3. an event that fails badly or is totally ineffectual
   同義詞：turkey, bomb

形容詞 dud:

1. failing to detonate; especially not charged with an active explosive

1. This battery is a dud.
   這電池是廢的。
2. Two of the fireworks in the box were duds.
   盒子里的煙火有兩個(gè)是壞的。
3. The new manager is a complete dud.
   新經(jīng)理完全是個(gè)廢物。

dud

n.（名詞）
A bomb, shell, or explosive round that fails to detonate.
啞彈：未爆炸的炸彈，炮彈或整發(fā)子彈
Informal One that is disappointingly ineffective or unsuccessful.
【非正式用語】 無用的人或物的：令人失望的無用的或不成功的人或物
duds Informal
duds 【非正式用語】
Clothing.
衣服
Personal belongings.
個(gè)人所有物

來源：
Middle English dudde [a cloak]
中古英語 dudde [斗篷]