IPA: /ˌprɛzərˈveɪʃənɪst/
KK: /prɛzərˈveɪʃənɪst/
A person who supports and promotes the protection and maintenance of natural environments, historical sites, or endangered species.
The preservationist worked tirelessly to protect the local wildlife from habitat destruction.
Preservationist → It is formed from "praeservare" (meaning to save or keep safe) and the suffix "-ist" (meaning a person who practices or is concerned with something). The word "preservationist" refers to a person who is concerned with the preservation or protection of something, particularly the environment or cultural heritage.
Think of someone who is dedicated to 'saving' ('praeservare') and protecting important things — that's what a preservationist does.