Á-deorcian

According to the Old English Dictionary:

á-deorcian

Substitute: To become dark, become tarnished:--Sunne áþýstrað and móna ádeorcað, Wlfst. 92, 21. Nú hit (a)deo(rcað) en tetrica aura est, An. Ox. 56, 200. Hwý is ðis gold ádeorcad (obscuratum)? Past. 133, 10. a-deorcian