There’s a subtle difference, although these are rare words so it’s hard to say whether they have different definitions or they merely appear in different contexts. Eorþ-fæst appears in only two prose texts in which it means ‘fixed in the earth’ (as a stone or a tree might be fixed in the earth). Eorþ-grāp is a hapax legomenon (appearing only once in extant Old English texts) and has been defined as ‘earth’s grip, grasp of the earth’. Eorþ-grāp appears in the poem The Ruin, which refers to the ancient builders of ruined buildings being cruelly confined to the ground (corpses buried).
Old English Wordhord 
Is eorþ-grāp the same as eorðfæstum (earthfast) or does it mean something more like Newton’s gravity.
LikeLike
There’s a subtle difference, although these are rare words so it’s hard to say whether they have different definitions or they merely appear in different contexts. Eorþ-fæst appears in only two prose texts in which it means ‘fixed in the earth’ (as a stone or a tree might be fixed in the earth). Eorþ-grāp is a hapax legomenon (appearing only once in extant Old English texts) and has been defined as ‘earth’s grip, grasp of the earth’. Eorþ-grāp appears in the poem The Ruin, which refers to the ancient builders of ruined buildings being cruelly confined to the ground (corpses buried).
LikeLike
Thank you! I was thinking that it could be a kenning instead. Graveyard or grave makes sense.
LikeLike