An adjective appearing as ᴱQ. erda “solitary, deserted” in the Qenya Lexicon of the 1910s under the early root ᴱ√ERE “remain alone” (QL/36).

Neo-Quenya: Since √ER remains tied to aloneness in Tolkien’s later writings, I’d retain ᴺQ. erda “solitary, deserted” for purposes of Neo-Quenya.