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

nud-

verb. to incline head, bend face down

A verb appearing as G. nud- “incline head, bend face down” in the Gnomish Lexicon of the 1910s (GL/61), probably based on the early root ᴱ√NUHU “bow, bend down; stoop, sink” (QL/68). There is a similar and probably-related verb G. nunta- “agree” appearing two lines below it.

Neo-Sindarin: For purposes of Neo-Sindarin, I would combine and adapt these verbs as ᴺS. nunna- “to incline head, bend face down, ✱nod; to assent, ✱agree” based on the later root √NU “sink, go down”, perhaps from primitive ✱nun-tā.