Gnomish
erethrin
adjective. isolated, solitary, lonely
tol erethrin
place name. Lonely Isle
i·glin grandin a·dol erethrin airi
*the fair towns of Holy Lonely Isle
erethog
adjective. isolated, solitary, lonely
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.