Noun
executionist (plural executionists)
(historical) A supporter of executionism.
About that time the " executionist movement " (Polish: "egzekucja praw"--"execution of the laws") began to take form. Source: Internet
The executionist movement (an attempt to prevent domination by the magnate families of Poland and Lithuania ) peaked at the Sejm in Piotrków in 1562–63. Source: Internet