Fnǽrettan

According to the Old English Dictionary:

fnǽrettan

p. te To snort, neigh, make a loud sound with the breath :-- Frendens hnǽgende, fnǽrettende (printed fnæs-, but see E. S. xi. 511), vel grymettende, frendit i. stridet dentibus, rugiet grymetteþ. Wrt. Voc.ii- 150. 52-55- fnærettan