The correct spelling of the word "un extremest" should be "an extremist." The reason for this is because the word "extremist" begins with a vowel sound, which is represented by the symbol /ɪ/ in the International Phonetic Alphabet (IPA). Therefore, the correct article to use before this word is "an" instead of "un." It is important to use proper spelling and grammar to ensure clear communication and understanding in both spoken and written language.
The term "un extremest" does not have an established etymology as it appears to be a combination of the negative prefix "un-" and the word "extremest". However, it is worth noting that "extremest" itself is not a widely recognized word in standard English. The proper adjective form of "extreme" is typically "most extreme" or "extremest" is simply a less commonly used variant.