A noun glossed “smoke, reek” appearing in the Qenya Lexicon of the 1910s, derived from the early root ᴱ√RUKU of the same meaning (QL/80).
Early Quenya
ruku-
verb. to steam, smoke, reek
ruku
noun. smoke, reek
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.
An intransitive verb glossed “to steam, smoke, reek” appearing in the Qenya Lexicon of the 1910s, derived from the early root ᴱ√RUKU “smoke, reek” (QL/80).