thyself
pron. C1 Advanced US //ˌðaɪˈsɛɫf// UK //θaɪsˈɛlf// thy·self
pron. yourself. You use this word in very formal or old-fashioned writing and speaking, mostly in religious or poetic contexts.
pron. the reflexive form of 'thou'. Used in archaic, poetic, or religious contexts to refer to oneself.
Thou shalt not harm thyself.
In the old manuscript, the author warned the reader to be careful of thyself when walking alone at night.
The poet's final stanza urges the reader to seek inner peace and to trust thyself rather than the shifting opinions of others.
From Middle English thy-selfe, thiself, thi-zelf, from Old English þīnes selfes, equivalent to thy + -self. Compare Middle English thou-self.