Sweorcan. i

According to the Old English Dictionary:

sweorcan. I

add :-- Þonne se man sceal sweltan, þonne swyrceð him fram þæs húses hrófe ðe hé inne bið, Verc. Först. 108, 1. Hé ásende þeóstru and swearc misit tenebras et obscuravit, Ps. L. 104, 28. I a. to grow black :-- Sweorcan and sweartian nigrescere, Chrd. 96, 10. sweorcan