Gnomish
bess
noun. wife
bess mora
a good wife
bedhril Archaic
noun. wife
nîr Archaic
noun. woman
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 (archaic) G. †bedhril “wife” in the Gnomish Lexicon of the 1910s, replaced in ordinary speech by G. bess (GL/22). It is a combination of the early root ᴱ√Beđ that was the basis for marriage words and the feminine agental suffix G. -(r)il (GL/22).
Neo-Sindarin: I would adapt this into Neo-Sindarin as ᴺS. bethril “spouse (f.)”, a combination of the later root ᴹ√BES “wed” and the same agental suffix, where sr became thr.