The Collaborative International Dictionary of English v.0.48:

Sahib \Sa"hib\, Saheb \Sa"heb\, n. [Ar. [,c][=a]hib master,
   lord, fem. [,c][=a]hibah.]
   A respectful title or appellation given to Europeans of rank.
   [India]
   [1913 Webster]

WordNet (r) 3.0 (2006):

sahib
    n 1: formerly a term of respect for important white Europeans in
         colonial India; used after the name

Moby Thesaurus II by Grady Ward, 1.0:

43 Moby Thesaurus words for "sahib":
   Esquire, Herr, Master, Mister, Sir, boss, bwana, chef, chief,
   church dignitary, don, ecclesiarch, effendi, elder, emir, employer,
   goodman, guru, husband, khan, liege, liege lord, lord,
   lord paramount, master, mirza, monsieur, overlord, padrone,
   paramount, paterfamilias, patriarch, patron, rabbi, seigneur,
   seignior, signor, sir, sirdar, sire, sirrah, starets, teacher