A lottery ticket that does not give a payout.
A failure of any kind.
A device or machine that is useless because it does not work properly or has failed to work, such as a bomb, or explosive projectile.
A loser; an unlucky person.
A warning signal (such as the call of sentry, the ringing of a bell, or the shriek of a siren) which turns out to have been given erroneously.
A thing or occurrence which initially causes fear, distress, etc. but which is subsequently recognized as being no cause for concern.