Sin-niht

According to the Old English Dictionary:

sin-niht

f. Substitute: sin-nihte, es; n. :-- Gársecg þeahte sweart synnihte blackest darkness covered ocean, Gen. 118. Þǽr eów is hám sceapen, sweart sinnehte there is a home assigned you, black darkness, Gú. 650. Hé geseah deorc gesweorc semian sinnihte sweart under heofonum he saw dark cloud lower, black night under heaven, Gen. 109. sin-niht