Beware, older languages below! The languages below were invented during Tolkien's earlier period and should be used with caution. Remember to never, ever mix words from different languages!

Gnomish

nudin

adjective. prone

An adjective appearing in the Gnomish Lexicon of the 1910s as G. {nûda “prone, face down” >>} nudin “prone”, based on G. nud- “incline head, bend face down” (GL/61).

Neo-Sindarin: For purposes of Neo-Sindarin, I would adapt this adjective as ᴺS. noden “prone, face down” based on the later root √NU “down”.