Qenya
lor-
verb. to sleep, to sleep, [ᴱQ.] slumber
olor
noun. dream
laure
noun. gold
lóre
noun. slumber
olar
noun. dream
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.
The verb ᴱQ. lor- “slumber” appeared in the Qenya Lexicon of the 1910s under the early root ᴱ√LORO “doze, slumber” (QL/56). The verb reappeared in a present participle form loralyar “asleep” in Koivienéni sentence which was probably composed in the late 1930s (VT27/7).
Neo-Quenya: I’d use lor- as the best available verb for “to sleep, slumber” for purposes of Neo-Quenya; see the entry on √(O)LOR for further discussion.