In witchcraft, a curse was an expressed wish typically issued by witches and warlocks that was issued as a means of causing misfortune or harm onto another or an object.
During a mission to Pyris VII in 2267, the landing party, which included Jackson, encountered the Ornithoid being Korob on the surface. Korob communicated through the crewman, who killed as he beamed aboard the USS Enterprise, warned Captain James T. Kirk, through Jackson, "There is a curse on your ship. Leave this place or you will all die." Ignoring the warning, Kirk, Spock and Leonard McCoy visited the planet's surface, where they encountered three witches. One witch repeated Korob's warning, telling Kirk and the others to "Go back! Remember the curse!" Later, after being captured and imprisoned by Korob, he observed how what they encountered, "dungeons, curses, skeletons and iron maidens, [were] all Earth manifestations," but he did not understand the significance. (TOS: "Catspaw")
In 2370, Ned Quint told Beverly Crusher his belief that the Howard family candle "has been a curse on your family for generations," adding that "If ye have a lick of sense, you'll listen to me right now and do away with it." (TNG: "Sub Rosa")
In 2371, Harry Kim, when asked by Captain Kathryn Janeway if Neelix had "concocted" any interesting food that morning, recited the ancient Chinese curse "May you live in interesting times." (VOY: "The Cloud")