The phrase "most onrushing" is spelled as [moʊst ɑnˈrʌʃɪŋ]. The word "most" is spelled as it is pronounced, with the long "o" sound and the "st" consonant cluster. "Onrushing" is spelled with a combination of the prefix "on-", which means "in," and the word "rushing," which indicates speed and movement. The stress falls on the second syllable, "rushing," which is pronounced with a short "u" sound and a "sh" consonant cluster. Overall, this phrase is intended to convey the idea of something moving forward with great speed and force.