What is "utamish"

Abu Musa Utamish (died June 6, 863) was a Turkish military officer of the Abbasid Caliphate. He played an important role in the first years of the period known as the Anarchy at Samarra, during which he rapidly became one of the most powerful officials in the government. He was appointed as vizier upon the caliph al-Musta'in's ascension in 862, but was assassinated after approximately a year in office.