As a verb, there is a similar sense of out but it also derives from the Dutch - to speak out, put up for sale or issue forth (as in water). The oral sense arrived in the 15th century. Mutter, however, is akin to mute, and probably onomatopoeic.Reuse content
IT IS better to utter rubbish than to utter utter rubbish. As an adjective, it is a shortening of the vowel in outer, which was its meaning before the extreme limits, so uttermost is now perhaps a tautology as an adjective. Utter is Old English, with Teutonic parallels, and was for long used to emphasise, say, rogues or ruin, but since the late 19th century has also been distinctly jocular (Gilbert and Sullivan's doing: "they are indeed jolly utter"). Milton was fond of utter, but "utter darkness" is Shakespeare's.