Correct spelling for the English word "un seeablest" is [ˈʌn sˈiːe͡ɪbə͡lst], [ˈʌn sˈiːeɪbəlst], [ˈʌ_n s_ˈiː__eɪ_b_əl_s_t] (IPA phonetic alphabet).
The word "unseeablest" does not have an established etymology because it is not a recognized English word. It appears to be formed by combining the prefix "un-" (indicating negation or reversal) with the adjective "seeable" (meaning capable of being seen) and the superlative suffix "-est" (indicating the highest degree of something within a group). However, this word does not follow standard English word formation patterns, and it is not commonly used or recognized.