The Collaborative International Dictionary of English v.0.48:

Harpist \Harp"ist\, n. [Cf. F. harpiste.]
   A player on the harp; a harper. --W. Browne.
   [1913 Webster]

WordNet (r) 3.0 (2006):

harpist
    n 1: someone who plays the harp [syn: harpist, harper]