A noun appearing as G. bloss “wheat” in the Gnomish Lexicon of the 1910s derived from ᴱ√mol- (GL/23), probably a variant of the early root ᴱ√MULU “grind fine” which had derivatives like ᴱQ. mulma “fine flour” (QL/63). If this derivation is correct, perhaps the original sense of bloss is something like “*grain to be ground/turned into flour”. The primitive form was probably *m’lossǝ where the initial ml became bl.

Neo-Sindarin: The root √MUL is still connected to flour words in Tolkien’s later writings, notably in Q. mulë “meal” in notes from 1968. Thus I think this Gnomish word can be salvaged as ᴺS. bloss “wheat”, but as a direct derivative of √MUL since short u generally became o in Sindarin of the 1950s and 60s.