The 11th king of Arthedain (LotR/1038). The initial element of his name is the prefix ar(a)- “noble” and its final element is probably the lenited form vegil of megil “sword”.
Sindarin
Arvegil
noun. royal sword
arvegil
masculine name. Arvegil
Elements
Word Gloss ar(a)- “noble, royal, high” megil “sword, longsword”
ar (prefix “high, noble, royal”) + megil (“sword”)