reformist

from WordNet (r) 3.0 (2006)

reformist
    adj 1: favoring or promoting reform (often by government action)
           [syn: {progressive}, {reformist}, {reform-minded}]
    n 1: a disputant who advocates reform [syn: {reformer},
         {reformist}, {crusader}, {social reformer}, {meliorist}]

from The Collaborative International Dictionary of English v.0.48

Reformist \Re*form"ist\, n. [Cf. F. r['e]formiste.]
   A reformer.
   [1913 Webster]