Fǽr-sceaða

According to the Old English Dictionary:

an;

fǽr-sceaða

m. A sudden or dangerous enemy; sŭbĭtum damnum infĕrens hostis :-- Ðæt he on ðam fǽrsceaðan feorh gerǽhte that he might reach the life of the dangerous enemy, Byrht. Th. 135, 62; By. 142. fær-sceaða