Thyself
来自Big Physics
wiktionary
From Middle English thy-selfe, thiself, thi-zelf, from Old English þīnes silfes, þīnre sylfre, etc., equivalent to thy + -self. Compare Middle English thou-self, Old English þē sylfum, þē selfum.
etymonline
thyself (pron.)
Middle English þi-self, from Old English þe self; see thy + self. One word from 16c. A pronoun used reflexively for emphasis after (or in place of) thou.
