I came across a reference to the Nawab of Oudh, wondered what exactly a nawab was, and thought “this is exactly the sort of thing Hobson-Jobson specializes in.” So I looked it up, and it wasn’t there. “It has to be there,” thought I, and tried possible alternate spellings: newab? nuwab? Nothing. Flipping through the book, I found it—under NABOB. Well, of course! In theory, I knew nabob was from nawab, but they occur in such different contexts and are pronounced so differently it’s hard to keep it in my head. Anyway, let Hobson-Jobson tell the story:
NABÓB (p. 610) , s. Port. Nababo, and Fr. Nabab, from Hind. Nawab, which is the Ar. pl. of sing. Nayab (see NAIB), ‘a deputy,’ and was applied in a singular sense* to a delegate of the supreme chief, viz. to a Viceroy or chief Governor under the Great Mogul, e.g. the Nawab of Surat, the Nawab of Oudh, the Nawab of Arcot, the Nawab Nazim of Bengal. From this use it became a title of rank without necessarily having any office attached. It is now a title occasionally conferred, like a peerage, on Mahommedan gentlemen of distinetion and good service, as Rai and Raja are upon Hindus.
Nabob is used in two ways: (a) simply as a corruption and representative of Nawab. We get it direct from the Port. nababo, see quotation from Bluteau below. (b) It began to be applied in the 18th century, when the transactions of Clive made the epithet familiar in England, to Anglo-Indians who returned with fortunes from the East; and Foote’s play of ‘The Nabob’ (Nabob) (1768) aided in giving general currency to the word in this sense.
*Dozy says (2nd ed. 323) that the plural form has been adopted by mistake. Wilson says ‘honorifically.’ Possibly in this and other like cases it came from popular misunderstanding of the Arabic plurals. So we have omra, i.e. umara, pl. of amir used singularly and forming a plural umrayan. (See also OMLAH and MEHAUL.)
There are, of course, the usual raft of citations, which are half the fun of H-J.