Doomsayer (noun)

1. A person who predicts or foretells disastrous events or doom.
2. A person who constantly speaks of impending disaster or negative outcomes.

Origin:

The word 'doomsayer' originated in the mid 17th century and comes from the phrase 'to say doom', meaning to predict or prophesize destruction or misfortune.

Examples:

1. The doomsayer predicted the end of the world, but it never came.
2. The doomsayer's constant negativity brought down the morale of the team.
3. The doomsayer's dire warnings of economic collapse turned out to be false.
4. The doomsayer's prophecy of a devastating earthquake never came to pass.
5. The doomsayer's constant complaints about the future were starting to wear on everyone's nerves.