Felagund
From Tolkien Gateway
Felagund was a surname given to Finrod by the Dwarves in their own tongue at the time of the delving of Nargothrond.
Etymology
From Khuzdul Felakgundu, "Hewer of Caves"[1]
Other versions
An early explanation by Tolkien was that the word meant "cave-prince" in Noldorin, from Quenya felya+cundu.[2]