archconspirator

English

Etymology

From arch- +‎ conspirator.

Noun

archconspirator (plural archconspirators)

1. A chief conspirator.
   • Records and Briefs New York State Appellate Division (page 2890)

     And the third archconspirator--and this is the bad one--the real archconspirator, this is the one with the pencil-thin, waxed mustache […]

   • 2016, Timothy W. Bjorkman, Verne Sankey: America's First Public Enemy:

     The jurors listened carefully while Eidem portrayed Fern Sankey as an archconspirator who drove her husband into crime and was intimately involved in all major details of Charlie Boettcher's abduction.