The 8th chieftain of the Dúnedain (LotR/1038). The initial element of his name is the prefix ar(a)- “noble” and its final element might be [N.] gost “terror” (as suggested by David Salo, GS/341).
Conceptual Development: In the draft of Appendix A of the Lord of the Rings, his name was first given as Arandost, revised to Aragost (PM/211).
aran (“king”) + gost (“dread”)