Gilruin
#2378
Regularely au turns to o/ó in polysyllables, cf. Q. Aurel, S. Ódhel, so I would expect óvennna- and óvennath. That it turns to a like in naur → Narwain only happens for ancient ā that shortened before consonant clusters and never became au in the first place.
A Sindarin adaptation of the neologism originally coined by Helge Fauskanger for his translation of the biblical New Testament into Quenya. Containing the elements au (a repurposing of the Quenya/Telerin word meaning "away"; and the verb menna-, or "to send."