high treason

treason against the sovereign or state.

Origin of high treason

Middle English word dating back to 1350–1400

If they had been guilty of high-treason, they should be duly arraigned.

The Life of John of Barneveld, 1614-23, Volume II. |John Lothrop Motley
Hunt and his associates were, after a short examination, conducted to solitary cells, on a charge of high-treason.

The History of England in Three Volumes, Vol.III. |E. Farr and E. H. Nolan
They even invoked the aid of England, and thus introduced foreign enemies on the soil of France, which was high-treason.

Beacon Lights of History, Volume VIII |John Lord
I fancy that he was found guilty of high-treason, was he not?

The Heir of Kilfinnan |W.H.G. Kingston

In his wrath he wrote vehement, insulting letters to the Emperor Francis, made himself guilty of high-treason.

A Conspiracy of the Carbonari |Louise Mhlbach

high treason

an act of treason directly affecting a sovereign or state