pourquoy
Pourquoy is an archaic French interrogative adverb meaning “why” or “for what reason.” In modern French the standard spelling is “pourquoi.” The form “pourquoy” was common in Early Modern French and appears in late medieval and Renaissance texts, as well as in religious and legal writings. The spelling reflects historical orthographic variation, with forms including pourquoï and pourquoy attested in older manuscripts. The suffix '-oy' corresponds to the modern suffix in '-oi,' and the final y often functioned as a vowel in historical usage.
Over the 17th and 18th centuries, French orthography shifted toward the modern form “pourquoi,” and “pourquoy”
In summary, pourquoy is the historical counterpart of pourquoi, retained in a minority of texts for antiquarian