The word "clergiest" can be tricky to spell because it contains two consecutive consonant clusters. In IPA phonetic transcription, the word is spelled /ˈklɜrdʒiɪst/. The first cluster, "cl," is followed by "er" and "gi," while the word ends with "est." While "clergy" is a noun meaning a body of ordained persons, "clergiest" is a superlative form used to describe the most "clergy-like" or "clergy-esque" person or thing. Despite its uncommon use, it's important to spell the word correctly when necessary.
The word "clergiest" does not have an established etymology as it is not a recognized English word. It might be a misspelling or a combination of the words "clergy" and "iest" (possibly intended as a superlative form of "clergy"). However, it is not a common or standard term in the English language.