Correct spelling for the English word "most semiyearly" is [mˈə͡ʊst sˈɛmɪjˌi͡əli], [mˈəʊst sˈɛmɪjˌiəli], [m_ˈəʊ_s_t s_ˈɛ_m_ɪ_j_ˌiə_l_i] (IPA phonetic alphabet).
The term "most semiyearly" is not a widely recognized word or phrase in the English language. It appears to be a combination of the adverb "most" (meaning very or extremely) and the word "semiyearly" (meaning occurring twice a year or every six months). However, the term "most semiyearly" is not commonly used, and its etymology is not well-established. It seems to be a unique combination created for a specific context or individual usage.