Greb was the name of a male Ferengi of legend.
Greb was a male from the village of Korpa who, while visiting the distant village of Noi, visited the shop of Obe to buy a can of beetle snuff. Greb overpaid Obe by half a slip of latinum, and Obe, an honest businessman, set out to return the money. Obe was killed on the road to Korpa by assassins hired by Greb, who then moved into Obe's house, took over his business, and married his widow. This story was used as an illustration of the First Rule of Acquisition. (DS9 reference: Legends of the Ferengi)