G-man (n.)

late 14c., "act of governing or ruling;" 1550s, "system by which a thing is governed" (especially a state), from Old French governement "control, direction, administration" (Modern French gouvernement), from governer "to steer, be at the helm of; govern, rule, command, direct," from Latin gubernare "to direct, rule, guide, govern," originally "to steer, to pilot"(see govern). Meaning "governing power" in a given place is from 1702. Compare governance.