Hisself

wiktionary

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From Middle English his-self, his self, his-selfe, his-selven, his selfen; equivalent to his +‎ -self.

etymonline

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hisself (pron.)

c. 1400; a shift in felt meaning of the first element of himself (q.v.) from dative to genitive created this new word, but the same process did not change herself.