Nawab (Eastern Nagari: নবাব/নওয়াব, Devanagari: नवाब, Perso-Arab: نواب) also spelt Nawaab, Navaab, Navab, Nowab and Nobab is an honorific title ratified and bestowed by the reigning Mughal emperor to semi-autonomous Muslim rulers of princely states in South Asia. Nawab usually refers to males; the female equivalent is begum or nawab begum. The primary duty of a nawab was to uphold the sovereignty of the Mughal emperor along with the administration of a certain province.The title of nawab was also awarded as a personal distinction by the paramount power, similar to a British peerage, to persons and families who ruled a princely state, for various services to the Government of British India. In some cases, these titles were also accompanied by jagir grants, either in cash revenues and allowances or land-holdings. During the British Raj, some of the chiefs or Sardars of large or important tribes were also given the title, in addition to traditional titles already held by virtue of chieftainship.The term nawab was originally used for the subahdar (provincial governor) or viceroy of a subah (province) or region of the Mughal empire.

Bio from Wikipedia - See more on Text under CC-BY-SA license