Sindarin name of the youngest son of Finwë (S/60), an adaptation of his father-name Q. Arafinwë (PM/344, 360). Finarfin did not leave Valinor with the other Noldor, and was the only Noldo who did not go into exile that received a Sindarin name (PM/360). The fin appearing at the beginning of his name is the same element fin appearing at the end, a Sindarin adaption of his father’s name Finwë (VT41/10). The middle element ar(a)- is a prefix meaning “noble”, so his name could be loosely interpreted as “Finwë, Noble Finwë”. His name was sometimes written Finarphin (MR/128, WJ/179), but the pronunciation would be the same.
Conceptual Development: In Silmarillion drafts from the 1930s, this character was named N. Finrod (LR/113), a name that was later reassigned to his eldest son.
the name probably has no meaning in S and is constructed in the way similar to Fingolfin; fin (reduced Finwë - his father's name) + ar (prefix “noble, royal”) + fin (reduced Arafinwë - his Quenya name)