The Elves who refused to journey to Aman, an agental formation of the ancient verb ava- “to refuse” with the common agental suffix -r(o) (VT47/13, WJ/371). This name most frequently appeared in its plural form Avari referring to this entire people (S/52).
Conceptual Development: The name ᴹQ. Avar(o) first appeared in plural form * in Tolkien’s linguistic notes from the 1930s with the gloss “The Departing”, and referred to those elves who left Middle-earth, whereas those who remained were referred to by the earlier name the ᴹQ. Lembi “Lingerers” (LR/169-170). Tolkien soon revised this name to refer to the Elves who remained behind, effectively replacing the term Lembi (LR/200). This name appeared in The Etymologies* with essentially the same derivation as given above (Ety/AB).
This plural name was known to the loremasters, but went out of daily use at the time of the Exile