A Curse-Breaker is a profession at the wizard's bank Gringotts, in which a wizard or witch disables or counters curses in ancient tombs or other historical sites, in order to bring back gold to Gringotts. It is speculated that Curse-Breakers are almost the equivalent of Muggle archaeologists.
It is said to be a very dangerous and serious profession, in which a wizard or witch could be killed as a result of an old curse, jinx, or hex. An O.W.L. in Arithmancy is required, as some banking and transacting will be done. Also, presumably, N.E.W.Ts in Defence Against the Dark Arts, Potions, Transfiguration, and Charms would be necessary, given the dangerous aspects of the job, as well as one in Ancient Runes. (However, this is merely a speculation).
Curse-Breakers do not have any known uniform; the Goblins running Gringotts generally do not care what the Curse-Breakers look like in terms of appearance or dress, as long as they bring much treasure back to the bank. Curse-Breakers are known to operate in Egypt and other areas of ancient magical importance.