Yours, Etc.: Origins and Uses of 8 Sign-Offs
1610s, from Latin machinator, agent noun from past participle stem of machinari "design, contrive, plot" (see machine (n.)).
"lay plots, intrigue," c.1600, a back-formation from machination, or else from Latin machinatus, past participle of machinari (see machination). Related: Machinated; machinating; machinator.