Qenya
usqe
noun. reek; dusk, twilight
hiswe
noun. fog
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 for “fog” in The Etymologies of the 1930s derived from primitive ᴹ✶khithme under the root ᴹ√KHITH “mist, fog” (Ety/KHIS; EtyAC/KHIS).
Neo-Quenya: The phonetic developments thm > þm̌ > þw > sw were consistent with Quenya phonology of the 1930s (PE19/44), but sometime around 1960, or shortly before, Tolkien revised these rules as discussed in the entry on the phonetic development of voiceless stops and aspirates before nasals (PE19/87 plus p. 88 note #88). I personally prefer the pre-1960 rules, and would retain this form for Neo-Quenya. If, however, you prefer the later rules, you should (a) stick to Q. hísë for both “mist” and “fog”, (b) revise this word to ᴺQ. ✱hitwe to fit later phonology, or (c) assume the primitive form was ✱khithwē rather than ᴹ✶khithme.