ˈthī adjective
Etymology: Middle English thy, thi, thin, from Old English thīn, gen. of thū thou — more at thine
archaic : of, belonging to, or connected with thee or thyself as possessor, as author, doer, giver, or agent or as object of an action
stretch out thy rod — Exod 8:16(Authorized Version)
thy slanders I forgive — Shakespeare
so thou be chastened by thy banishment — Alfred Tennyson
— used especially in biblical, ecclesiastical, solemn, or poetic language, and to some extent in the speech of Friends especially among themselves; compare thee I, thou , your I