Stithy, a blacksmith's forge.
Strait, narrow, cramped.
Stripling, a young man just grown up; cf. youngling.
Sunder, to separate, e.g. "We wend on the sundering ways."
Sun-dog, a bright spot like a faint image of the sun, seen near it in cloudy weather.
Swaddling, anything that wraps or enfolds, e.g. the coils of Fafnir passing over Sigurd in the pit are called "the swaddling of death."
Swart-haired, dark-haired.
Swathe, the long line of mown corn behind a reaper; cf. "swathes of the sword," i.e. heaps of dead in battle.
Targe, a shield.
Tarry, to wait, to linger, e.g. "Tarry till I say a word."