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.
gath
noun. neck
gath Archaic
noun. gloom, blight
grûd
noun. cavern
rodos
noun. cavern
A noun for “cavern” in the Gnomish Lexicon of the 1910s based on the early root ᴱ√roto (GL/65). In early editions of the Gnomish Lexicon as published, the form was incorrectly given as rodrin, but errata confirmed that word actually meant “cylindrical” and the word for “cavern” was properly rodos (PEE for issue 11), as reported by Christopher Tolkien (LTA2/Rothwarin).
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.
An (archaic) word for “gloom, blight” in the Gnomish Lexicon of the 1910s with stem-form gadh-, apparently derived from a variant of ᴱ✶ı̯ādh which was the ancient final element of G. Garioth (GL/37). As such it clearly based on the early root ᴱ√YAÐA with Gnomish form gadh- (QL/105).