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.
atalta-
verb. to collapse, fall in, fall down, slip down in ruin
ataltare
noun. collapse
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 verb in The Etymologies of the 1930s glossed “collapse, fall in”, an elaboration of ᴹQ. talta- “slope, slip, slide down” under the root ᴹ√TALAT “to slope, lean, tip” (Ety/TALÁT). The verb talta- seems to refer to the process of sliding down or collapsing, while atalta- is the completion of that process = “✱total collapse, falling into ruin”. The past tense atalante of this verb appeared in various versions of the Lament of Atalante and associated notes from the 1930s and 40s, with glosses like “down-fell”, “fell down” and “slip down in ruin” (LR/47; SD/247, 249).