Sith :: Sith (prep., adv., & conj.) Since; afterwards; seeing that..
Sithe :: Sithe (v. t.) To cut with a scythe; to scythe.
Sithen :: Sithen (adv. & conj.) Since; afterwards. See 1st Sith.
Sithens :: Sithens (adv. & conj.) Since. See Sith, and Sithen..