Grennian

According to the Old English Dictionary:

grennian

p. ode To grin, shew the teeth as an expression of pain, anger, etc; ringere :-- Ic grennige ringo, Ælfc. Gr. 28; Som. 31, 63. He grennade and gristbitade he grinned and gnashed his teeth, Exon. 74 b; Th. 278, 11; Jul. 596. Grenniendum welerum hleahter forþbringan ringentibus labiis risum proferre, Scint. 55, Lye. [Laym. A. R. grennen: Prompt. Parv. grennyn ringo: Icel. grenja to howl: O. H. Ger. grennat mutiet.] grennian