THYSELF', pronoun [thy and self.] A pronoun used after thou, to express distinction with emphasis. 'Thou thyself shalt go; ' that is, thou shalt go and no other. It is sometimes used without thou, and in the nominative as well as objective case. These goods thyself can on thyself bestow.
Source: Webster's 1828 American Dictionary ↗ · public-domain · returned verbatim, no AI