Dud

What is Dud ?

Dud is (adj) false (informal.) He paid me with a dud £10 note. Synonym useless. Antonym usable (noun) 1. a false banknote The £50 note was a dud. 2. something which does not work properly Most of the fireworks in the box were duds.

 

source: Easier English, Student Dictionary Upper Intermediate Level