ul (stem “hideous, horrible”) + gwarth (“betrayer”)
Sindarin
ulwarth
masculine name. Ulwarth
Elements
Word Gloss ul- “*ugly” gwarth “betrayer”
Ulwarth
noun. hideous betrayer
uanui
hideous
uanui (monstrous); no distinct pl. form. Also prefix ul- (ugly) (only found as initial element of names, like Ulwarth).
uanui
hideous
(monstrous); no distinct pl. form. Also prefix ul- (ugly) *(only found as initial element of names, like Ulwarth)*.
ulunn
deformed and hideous creature
(monster), pl. ylynn. *(The archaic form ulund and the later form ulun is cited in LR:396 s.v.*
Son of the traitorous Easterling chief Ulfang (S/157). This name seems to be Sindarin, and therefore was probably not his true name. It seems to be a combination of [N.] ul- “✱ugly” and the lenited form of [N.] gwarth “betrayer”.
Conceptual Development: This character was named N. Ulwar when he first appeared in Silmarillion drafts from the 1930s, later changed to N. Ulwarth (SM/320, LR/147). This second name appeared in The Etymologies as a combination of ᴹ√ULUG and N. gwarth, the source of the derivation given above (Ety/ÚLUG, WAR).