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.
ruin
adjective. inhabited, tilled
fectha-
verb. to destroy, ruin, spoil
A verb appearing as G. fectha- “destroy, ruin, spoil” in the Gnomish Lexicon of the 1910s, related to G. fêg “bad, poor, wretched” (GL/34) and thus probably based on an unattested the early root ✱ᴱ√FEKE.
Neo-Sindarin: For purposes of Neo-Sindarin I would adapt this verb as ᴺS. feitha- “destroy, ruin, spoil” based on a Neo-Root ᴺ√PHEK, with the vocalization of *ekth* to *eith*.
teraith
noun. waste, ruin, destruction
A noun appearing as G. teraith or tereth “waste, ruin, destruction” in the Gnomish Lexicon related to the verb G. tertha- “devour, destroy” (GL/70).
Neo-Sindarin: Since I retain ᴺS. tertha- “destroy” for purposes of Neo-Sindarin, I would adapt this noun as ᴺS. terthas “waste, ruin, destruction” to more closely align to the verb.
cantha
noun. flame
A noun in the Gnomish Lexicon of the 1910s glossed “flame” (GL/25), probably based on the early root ᴱ√KṆŘṆ [KṆÐṆ] “shine” (QL/47).
gwilthi
noun. peace
sâ
noun. fire
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 word for “inhabited, tilled” in the Gnomish Lexicon of the 1910s listed below G. rû “dwelling, house” (GL/66), thus likely related to ᴱQ. rú “dwelling, village” derived from the early root ᴱ√RU’U (QL/80).