IPA: /ɪnˈstɪtʃuːtər/
KK: /ɪnˈstɪtʃʊtər/
A person who starts or establishes something, such as a system, organization, or rule.
The instituter of the new policy was praised for their innovative approach.
Instituter → The word is derived from the Latin root "institut-" (from "instituere", meaning to set up or establish) and the suffix "-er" (meaning a person who). Thus, an instituter is a person who establishes or sets up something.
Think of someone who 'establishes' ('institut-') something — that's what an instituter does.