The word Naib (Arabic: نائب) has been historically used to refer to any local leader in some parts of Ottoman Empire and eastern Caucasus (e.g. during Caucasian Imamate).
Today, the word is used to refer to directly-elected legislators in lower houses of parliament in many Arabic-speaking areas in order to contrast them against officers of upper houses (or Shura). The term Majlis al-Nuwwab (Arabic: مجلس النواب, literally council of deputies) has been adopted as the name of several legislative lower houses and unicameral legislatures.
Read more about this topic: Nawab, Derived Titles