Word/phrase for "the one that brings bad luck" (e.g. to a group)

Jinx is likely the word you are looking for, as in

I have always considered myself jinxed but it is also possible to say

I have always considered myself a jinx

Wikipedia: Jinx

• A type of curse placed on a person that makes them prey to many minor misfortunes and other forms of bad luck;
• A person afflicted with a similar curse, who, while not directly subject to a series of misfortunes, seems to attract them to anyone in his vicinity.

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A word which might be applied to a person is Jonah, from the Biblical story of Jonah (of whale fame).

He was taking a sea voyage and storms threatened to sink the ship because God was displeased with him fleeing. The sailors drew lots to find the cause of the bad luck, chose Jonah and dumped him overboard to get rid of him. The storm stopped immediately.

The full story is in Jonah Chapter 1.

An alternative term derived from traditional folk spirituality that developed from a number of West African, Native American and European spiritual traditions is:

Hoodoo: (fromTFD)

• (Other Non-Christian Religions) a variant of voodoo
• a person or thing that brings bad luck
• bad luck

Cassandra famously foretold ill fortunes and calamities which nobody believed in, she was said to be cursed by Apollo after she had refused his sexual advances. In that sense a Cassandra would be anyone (man or woman) who issues a warning about an awful event and whose prediction is later verified. The misfortune falls on others and not on the teller.

Sometimes the name Cassandra is applied to those who can predict rises, falls, and particularly crashes on the global stock market, as happened with Warren Buffett, who repeatedly warned that the 1990s stock market surge was a bubble, attracting to him the title of 'Wall Street Cassandra'.

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