Early Noldorin
thalf
noun. grease
gwas
noun. field
There are more words but they are from Tolkien's earlier conceptional periods. Tolkien likely changed these words as he evolved the aesthetics and completeness of the languages. You may even find languages that Tolkien later rejected. Do not mix words from different time periods unless you are familiar with the phonetic developments.
Below: Tolkien's Late Period (1950–1973). These are from Tolkien's late conceptual period — his most settled forms of the languages. Prefer these over the earlier ones above when composing new text.
A noun appearing as ᴱN. thalf “grease” in Early Noldorin Word-lists of the 1920s, a derivative of primitive ᴱ✶stalqe (PE13/153). It is probably unrelated to similarly formed words like ᴱN. thala “valiant” and ᴱN. thalion “warrior hero” from the same document whose primitive forms begin with stalg- (PE13/153).
Neo-Sindarin: Since this word coexisted with ᴹ√STALAG derivatives in the 1920s, I would assume the same would be true in Tolkien’s later writing. Therefore I’d retain this word as ᴺS. thalph “grease” for purposes of Neo-Sindarin, revised to fit the phonology of later Sindarin and derived from some otherwise-obscure triconsonantal root.