The correct spelling of the word is "most iterating". Iterating means repeating a process or sequence. To pronounce it correctly, use the International Phonetic Alphabet (IPA) phonetic transcription: /məʊst ˈɪtəreɪtɪŋ/. The first syllable "məʊst" is pronounced like "mo-st" with a long o sound. The second syllable "ɪtəreɪtɪŋ" is pronounced with short i sound as in "it", followed by "ter" and an "ating" sound like in "baiting". So, the correct pronunciation is "mo-st it-er-ay-ting".