1)
What is the meaning of "Asof Asef"?
1.
Rashi: It is an expression of eradication, like "v'Asafta Nafshecha" (Shoftim 18:25) of Michah. There should be another Aleph in Asef, it is omitted. There are many words like this, e.g. "v'Lo Yahel Sham Aravi" (Yeshayah 13:20) is like Lo Ye'ehal with an Aleph.
2.
Radak: Asof is Makor (like a gerund); it refers to eradication, like "v'Asafta Nafshecha v'Nefesh Beisecha" (Shoftim 18:25). Asef is like "Safu Tamu" (Tehilim 73:19); the middle letter of the root is omitted. Also "Asof Asifem" (Yirmeyah 8:13) - all living beings will be eradicated from the land, i.e. Eretz Yisrael. First it gives the Klal, and afterwards explains.
