Fyrnum

According to the Old English Dictionary:

fyrnum

ad horrĭbĭlĭter :-- Ðonne cymþ forst fyrnum cald then cometh frost intensely cold, Cd. 17; Th. 20, 28; Gen. 316: 38; Th. 50, 16; Gen. 809. v. firnum. fyrnum

Related words: With horror, horribly, intensely;