The phrase "most chi chi" is typically used to describe something that is considered excessively or ostentatiously fashionable. The spelling of "chi chi" reflects the word's origin in French, where it is pronounced /ʃi ʃi/. In English, the "ch" sound is often softened to a "sh" sound in the middle of words, as in "machine" (/məˈʃiːn/). Therefore, the correct IPA transcription for "most chi chi" would be /məʊst ʃi ʃiː/.