Gnomish
tertha-
verb. to devour, destroy
tercha-
verb. to devour, destroy
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 verb appearing as G. tertha- or tercha- “devour, destroy” in the Gnomish Lexicon, perhaps related to G. terch “worm” [= “✱worm eaten”] (GL/70) and thus ultimately derived from the early root ᴱ√TEŘE “pierce, boring” (PME/91).
Neo-Sindarin: Since √TER “pierce” survives in Tolkien’s later writings, I would retain ᴺS. tertha- “destroy” for purposes of Neo-Sindarin, originally with the sense “✱fill with holes”, but for “devour” I would use ᴺS. ammad-.