A noun appearing as G. tump “shed” in the Gnomish Lexicon of the 1910s (GL/71), clearly a cognate to ᴱQ. tumpo “shed, barn” which was derived from either ᴱ√TṂPṂ or ᴱ√TUPU (QL/93, 95).

Neo-Sindarin: Since √TUP “cover” survived in Tolkien’s later writings, I think this word can be salvaged as ᴺS. tump “shed”, though it does conflict with [N.] tump “hump”.