Definition from Wiktionary, the free dictionary
In colloquial usage in English since 1612, from Urdu, from Persian, from the honorific plural of Arabic نائب (nā’ib, “deputy”).
nabob (plural nabobs)
- An Indian ruler within the Mogul empire; a nawab.
- (by extension) Someone of great wealth or importance.
- (by extension) A person with a grandiose style or manner.
someone of great wealth
- See also Wikisaurus:wealthy
Derived terms 
- Nob Hill (San Francisco)
- Nabobs: A Study of the Social Life of the English in the Eighteenth-Century, Percival Spear, Oxford University Press, London 1938; New Edition OUP, USA: 1998.
- Durham's Place-Names of the San Francisco Bay Area, David L. Durham, Quill Driver Books, California: 2000.