Wikipedia
Janab (جناب) is a rank title in Persian, which may be rendered as Excellency.
At the court of Persia's Shahanshahs of the imperial Qajar dynasty, precedence for non-members of the dynasty was organised in eight protocollary classes, generally coupled to various offices and qualities; the highest of these, styled Nawab, was usually reserved for princes, while the six classes were awarded to various ministers, officers, commanders, Muslim clergy and so on. Ranking only below Nawab and Shakhs-i-Awwal (usually present and former Prime Ministers), Janab was the style borne by senior Ministers of State, high ranking clergy, Grand Ministers of State, Governors-General of major provinces, the Commander-in-Chief of the Army, etc.; it ranked above Amir or Khan, 'Ali Jah Muqarrab, 'Ali Jah, 'Ali Sha'an and 'Ali Qadir.
The compound style Janab-i-Ashraf ( Ashraf being a provincial aristocrat) was borne by prime ministers and can be translated as His Serene Highness.