A word appearing as G. mûst “byre, cowhouse” in the Gnomish Lexicon of the 1910s, a combination of G. mû “ox” and ost “enclosure” (GL/58). Tolkien wrote ŭ in parenthesis after this word, perhaps indicating the proper form should be mŭst, since a long vowel before a cluster like st is very peculiar.

Neo-Sindarin: I would adapt this word as ᴺS. munnost, using the later word S. mund as its initial element.