instigatrix

Learned borrowing from Latin īnstīgātrīx. By surface analysis, instigator +‎ -trix.

instigatrix (plural instigatrices)

1. Female equivalent of instigator.
   • 1811, Biographie Moderne, volume I, page 24:

     Better perhaps would it have been for the accused had she had no other advocates than her innocence and her firm imposing demeanour ; but her death was resolved on, and two days after she was condemned as “ the instigatrix of the crimes committed by the last tyrant of France ; as having herself maintained a correspondence with foreign powers, particularly with her brother the king of Bohemia and Hungary, with those emigrants who were formerly French princes, and with perfidious generals […]

From īnstīgō, īnstīgātum (“to incite, instigate”, verb) +‎ -trīx f (“-ess”, agentive suffix).

• (Classical Latin) IPA^(key): [ĩː.stiːˈɡaː.triːks]
• (modern Italianate Ecclesiastical) IPA^(key): [in.st̪iˈɡaː.t̪riks]

īnstīgātrīx f (genitive īnstīgātrīcis); third declension

1. female equivalent of īnstīgātor (“stimulator, instigator”)

Third-declension noun.

• “instigatrix”, in Charlton T. Lewis and Charles Short (1879) A Latin Dictionary, Oxford: Clarendon Press
• “instigatrix”, in Charlton T. Lewis (1891) An Elementary Latin Dictionary, New York: Harper & Brothers