IPA: /ˌsɛrəˈmoʊnɪəlist/
KK: /sɛrəˈmoʊnɪəlist/
A person who enjoys or is skilled in performing ceremonies, especially in a religious or formal context.
The ceremonialist led the wedding with great enthusiasm and attention to detail.
Ceremonialist is formed from "ceremony" (from Latin "caerimonia", meaning a religious or formal observance) and "-ist" (meaning a person who practices or is concerned with). The word refers to a person who is dedicated to or specializes in ceremonies.
Think of a 'ceremony' as a formal observance, and the '-ist' means a person involved in that practice. So, a ceremonialist is someone who specializes in ceremonies.