1. A person who believes in or advocates for social, political, or technological progress
   "The progressionist argued for sweeping reforms in education and healthcare"
    
2. [archaic] (evolutionary biology) a person who believes in the theory that evolution follows a predetermined path of increasing complexity or perfection
   "Some progressionists argue that human evolution is moving towards a more advanced state"

1. Relating to or characterized by a belief in progress
   "Her progressionist views shaped her approach to urban planning and social policy"

Derived forms: progressionists