Strong’s Greek
G4688 — spekoulator
The entry below is Strong’s own definition (1890, public domain), and every verse where the word occurs.
σπεκουλάτωρ
spekoulator — pronounced spek-oo-lat'-ore
of Latin origin; a speculator, i.e. military scout (spy or (by extension) life-guardsman):--executioner.
1 occurrence in the KJV.
Mark 6:27
And immediately the king sent an executioner, and commanded his head to be brought: and he went and beheaded him in the prison,