What is "rain-in-the-face"

Rain-in-the-Face ( Lakota: Ité Omáǧažu (in Standard Lakota Orthography) (c. 1835 – September 15, 1905) was a warchief of the Lakota tribe of Native Americans. His mother was a Dakota related to the band of famous Chief Inkpaduta. He was among the Indian leaders who defeated George Armstrong Custer and the U.S. 7th Cavalry Regiment at the 1876 Battle of Little Big Horn.