Early Noldorin
arn
noun. child, child, [G.] son
gó
noun. son
lhaur
adjective. red
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 word appearing as G. arn “son” in the Gnomish Lexicon of the 1910s (GL/20), also appearing with the same form and meaning in Gnomish Lexicon Slips modifying that document, but with a new plural form eirn (PE13/110). The word reappeared in Early Noldorin Word-lists of the 1920s but there its gloss was changed from “son” to “child” (PE13/137). In the Early Noldorin Dictionary of the 1920s its only gloss was “child” (PE13/160). There is no sign of this word thereafter.