dud:
(plural: ‘duds‘; pronunciation: the letter ‘u’ rhymes with the letter ‘u’ in the word “but”)
a person (or a thing) that is worthless, valueless, useless, or unable to serve a desired purpose, and proved to be a failure,

a dud, being unsuccessful
When he was unsuccessful in his business, Rooney started working for a company, and later when he was given a sack for his inefficiency by his employer, he realised that he was a dud, unfit for for anything.
A woman on a date feels that her date is a dud if he doesn’t flirt and a stud if he flirts.
The manager thinks that all his staff are duds, not knowing how to handle any crisis on their own.
Most duds in the society are those who stick to their principles and do not compromise with the changes they see around them.

a dud missile, failed to launch
