The Collaborative International Dictionary of English v.0.48:

Rentier \Ren`tier"\ (r?N`ty?"), n. [F. See 5th Rent.]
   One who has a fixed income, as from lands, stocks, or the
   like.
   [1913 Webster]

WordNet (r) 3.0 (2006):

rentier
    n 1: someone whose income is from property rents or bond
         interest and other investments