legitimist

from The Collaborative International Dictionary of English v.0.48

Legitimist \Le*git"i*mist\ (-m[i^]st), n. [Cf. F.
   l['e]gitimiste.]
   1. One who supports legitimate authority; esp., one who
      believes in hereditary monarchy, as a divine right.
      [1913 Webster]

   2. Specifically, a supporter of the claims of the elder
      branch of the Bourbon dynasty to the crown of France.
      [1913 Webster]