Ge-giscan

According to the Old English Dictionary:

ge-giscan

p. te, de To stop up, close:--Gegiscte (gigiscdæ, Ep., gescdae, Erf., gigisdae, Ld.) oppilavit, clausit, Txts. 83, 1447. Gegiscde, betýnde oppilavit, Wrt. Voc. ii. 65, 18. ge-giscan