York-born conspirator executed in 1606 (6)
I believe the answer is:
fawkes
(Other definitions for fawkes that I've seen before include "Guy . . . . . . burned in effigy on Nov 5th" , "Guy -- (Gunpowder Plot)" , "Gunpowder plotter" , "Guy --, conspirator" , "Guy -- (November 5)" .)