1. (noun)flop, dud, washout someone who is unsuccessful
2. (noun)misfire, dud an explosion that fails to occur
3. (adj)turkey, bomb, dud an event that fails badly or is totally ineffectual "the first experiment was a real turkey"; "the meeting was a dud as far as new business was concerned"
4. (adj)dud failing to detonate; especially not charged with an activeexplosive "he stepped on a dud mine"