Early Quenya
malo
noun. moth
malo
noun. rust
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 ᴱQ. malo “moth” in the Qenya Lexicon of the 1910s derived from primitive ᴱ✶[mal]wǝ under the early root ᴱ√MALA “crush, squeeze, pulp” (QL/58). It had a plural malwi, and in the Poetic and Mythological Words of Eldarissa it was given the stem form of malu-.
Neo-Quenya: This word conflicts with later words like ᴹQ. malo (malu-) “pollen, yellow powder” (Ety/SMAL) or “rust” (PE21/12; PE15/77), making its continued validity as “moth” rather questionable. However, the only other attested Elvish “moth” word is G. fufril of unclear etymology (GL/36), making it very challenging to adapt to Neo-Quenya. Thus I currently recommend retaining ᴺQ. malo for “moth”, as a derivative of the later root ᴹ√MBAL, but altering its stem form to malo- (< ✱mbalō) to make it more distinct from the “pollen, rust” words.