This might be just a supplemental entry adding to an entry in the Main Volume.
gánung
.Add: opening of the mouth in scorn or abuse (? cf. Ps. Th. 108, I under gánian) :-- Gánung gannatura (cf. gannature bysmires, 85,67), Wrt. Voc. ii. 70, 30. [Ganynge oscitatus, Prompt. Parv. 185 : hiatus, Cath. Ang. 149.]
Cite the scanned version of the original dicionary like this:
Toller, T. Northcote, and Joseph Bosworth. "gánung." An Anglo-Saxon Dictionary: Based on the Manuscript Collections of the Late Joseph Bosworth : Supplement. Oxford: Clarendon Press, 1921. 282.