Correct spelling for the English word "Importancy" is [ɪmpˈɔːtənsi], [ɪmpˈɔːtənsi], [ɪ_m_p_ˈɔː_t_ə_n_s_i] (IPA phonetic alphabet).
The word importancy does not have its own entry in most dictionaries, and it is not commonly used in modern English. However, it can be considered a variant or less common form of the word importance.
The word importance originated from the Middle English word importaunce, which came from the Old French word importance. This Old French term was derived from the Latin word importans, which is the present participle of the verb importare meaning to bring in, bring forward.
Overall, importancy seems to be a less recognized or used variant of importance.