The Collaborative International Dictionary of English v.0.48:

Annuitant \An*nu"i*tant\, n. [See Annuity.]
   One who receives, or its entitled to receive, an annuity.
   --Lamb.
   [1913 Webster]

WordNet (r) 3.0 (2006):

annuitant
    n 1: the recipient of an annuity