jinx /(jĭṉks)/

jinx

n.
  1. A person, object, influence, or supernatural being which is supposed to bring bad luck or to cause things to go wrong. [Slang]

jinx

v. t.
  1. To bring bad luck to; to cause to malfunction or go wrong; as, some superstitious people are reluctant to predict success for fear it will jinx them. [Slang]