The spelling of the word "most withstanding" follows English language rules for the pronunciation of consonant clusters in the middle of words. The "st" consonant cluster is pronounced as [st], with the "s" sound followed by the "t" sound. The vowel in the stressed syllable is "a", pronounced as [ɑː]. Therefore, the IPA transcription of "most withstanding" is /məʊst wɪθˈstændɪŋ/. This word can be used to describe something that withstands the most or that is the best at withstanding a particular challenge or test.
The phrase "most withstanding" is not a commonly used phrase in contemporary English. However, if you are referring to the separate words "most" and "withstanding", I can provide their etymology:
1. Most: The word "most" comes from the Old English word "mǣst" which means "greatest" or "largest". It can be traced back to the Proto-Germanic word "*maistaz". This word evolved into the Middle English term "moste" before becoming its present form, "most", in modern English.
2. Withstanding: The word "withstanding" is derived from the combination of the prefix "with-" and the verb "stand". The prefix "with-" is from the Old English word "wið" which means "against" or "opposite". The verb "stand" comes from the Old English word "standan" with similar meaning.