jinx 
(jĭngks)
(jĭngks)n.
1. A person or thing that is believed to bring bad luck.
2. A condition or period of bad luck that appears to have been caused by a specific person or thing.
tr.v. jinxed, jinx·ing, jinx·es
To bring bad luck to.
[Possibly from jynx, wryneck (from its use in witchcraft), from Latin iynx, from Greek iunx, perhaps from iuzein, to call, cry.]