Evolutionist

Part of speech: noun

Definitions

1. A person who studies the gradual progression of biological changes and the adaptation of species over generations
2. A scholar or advocate for the theory that species evolve through natural selection and environmental influence in a gradual process
3. An individual who emphasizes the study and interpretation of organisms' development and species transformation over time

Etymology: The suffix doing the work here is "-ist", and its history runs deeper than the English word. It traces back through Latin "-ista" and Old French "-iste" to Ancient Greek "-ιστής" (-istēs), a suffix used for people who practise or follow something, as in "-ιστής" forms for those who work at or believe in a particular thing. Its ancestry reaches into Proto-Hellenic and beyond to Proto-Indo-European roots, but the story that matters for English is how the suffix was borrowed and reused. English took "-ist" through Middle English, and it became one of the most productive endings in the language, attaching to nouns to name a practitioner or adherent. "Evolutionist" is simply "evolution" with that suffix added, so it names a person who follows or champions the idea of evolution.