Early Quenya
rue
noun. rest, stillness, remaining, steadfastness
Beware, older languages below! The languages below were invented during Tolkien's earlier period and should be used with caution. Remember to never, ever mix words from different languages!
A noun appearing as ᴱQ. rue “rest, stillness, remaining, steadfastness” in the Qenya Lexicon of the 1910s under the early root ᴱ√RU’U, the noun form of ᴱQ. rua “steady, still, tranquil” (QL/80).
Neo-Quenya: For purposes of Neo-Quenya, I would retain ᴺQ. ruë derived from a Neo-Root ᴺ√RUH, but with a slightly revised meaning “stillness, ✱steadiness, tranquility” to be more compatible with its adjective.