Noun. From Ubykh.
“The metal ornament found at the head of a whip”
This word also has a double meaning, notably an idiomatic phrase describing someone whose kind appearance or friendly nature is deceptive. For those who are interested, Ubykh was spoken in an area between Russia and Georgia, but it is now classed as an extinct language with the last speaker dying in 1992, according to this information over on Wikipedia.