arbiter elegantiarum

noun

arbiter el·​e·​gan·​ti·​a·​rum -ˌe-lə-ˌgan-shē-ˈa-rəm 

-ˈer-əm

: a person who prescribes, rules on, or is a recognized authority on matters of social behavior and taste

Word History

Etymology

borrowed from Latin, literally, "arbiter of refinements"

First Known Use

1728, in the meaning defined above