The word 'uttermost' is a double superlative construction, combining the comparative sense of 'utter' (meaning outer or further out) with the superlative suffix '-most'. Its Old English ancestor, 'ūtemest', literally meant "outermost" or "farthest out," a meaning still evident in its earliest uses. Over time, the spatial sense of "farthest in distance" broadened into a more abstract and intensive meaning, signifying the greatest possible degree or the extreme limit of something. This evolution from a literal physical extreme to a figurative or quantitative extreme illustrates a common semantic pathway in English vocabulary development.

Structure: utter (outer) + most (superlative suffix) 'utter' originates from Old English 'ūtera, ūterra' (outer, comparative of 'ūt' meaning out), functioning as a comparative adjective. 'most' originates from Old English 'mǣst' (greatest, superlative of 'micel' meaning great), functioning as a superlative suffix.