Dǽd-weorc

According to the Old English Dictionary:

es;

dǽd-weorc

n. A work of works, great work; facinus egregium :-- Hereþreátas for ðam dǽdweorce Drihten héredon the army-bands praised the Lord for that great work, Cd. 170; Th. 214, 26; Exod. 575. dæd-weorc