reformist

Etymology

reform + -ist. Originated around the end of the 16th century.

adj

1. Advocating reform of an institution or body.
   … all the prose is German, all reformist, all moralising, and has little or practically no echo of antiquity. 1913, Émile Faguet, translated by Sir Home Gordon, Initiation into Literature
2. Specifically, advocating reform and the gradual accumulation of small changes, as opposed to revolutionary action.

noun

1. One who advocates reform (of an institution).
2. Specifically, one who advocates reform of society and the gradual accumulation of small changes, as opposed to revolutionary action.
3. (dated, 17th C.) An advocate of reform in the Church of England; a Reformer.
4. (dated, 18th century) An advocate or supporter of political reform in the United Kingdom. (Common from ca 1790 to 1830.)
5. A member of a reformed religious denomination.