Ge-syngian

According to the Old English Dictionary:

-singian;

ge-syngian

p. ode, ade; pp. od, ad To sin, perpetrate crime, commit adultery; peccāre, mæchāri :-- Ðæt ǽlc ðæra ðe wíf gesyhþ and hyre gewilnaþ, eallunga ðæt se gesyngaþ on hys heortan quia omnis, qui vīdĕrit mŭliĕrem ad concŭpiscendum eam, jam mæchātus eam in corde suo, Mt. Bos. 5, 28. Nú is geséne ðæt we gesyngodon now it is seen that we have sinned, Cd. 218 ; Th. 278, 31; Sat. 230. Ðæt wæs feohleás gefeoht, fyrenum gesyngad that was a priceless fight, criminally perpetrated, Beo.Th. 4874; B. 2441. ge-syngian