Source : Webster's Revised Unabridged Dictionary (1913)

Baboo \Ba"boo\, Babu \Ba"bu\ (b[aum]"b[=oo]), n. [Hind.
   b[=a]b[=u] ]
   A Hindoo gentleman; a native clerk who writes English; also,
   a Hindoo title answering to Mr. or Esquire. --Whitworth.

Source : WordNet®

babu
     n : used as a Hindi courtesy title; equivalent to English `Mr'
         [syn: {baboo}]