All 3 Uses

treason
in
Henry IV, Part 2
(Auto-generated)

Good tidings, my Lord Hastings; for the which I do arrest thee, traitor, of high treason: And you, lord archbishop, and you, Lord Mowbray, Of capital treason I attach you both.†
Scene 4.2

treason = an act of betrayal
Good tidings, my Lord Hastings; for the which I do arrest thee, traitor, of high treason: And you, lord archbishop, and you, Lord Mowbray, Of capital treason I attach you both.†
Scene 4.2
Some guard these traitors to the block of death, Treason's true bed and yielder up of breath.†
Scene 4.2 *

Definitions:

(1) (treason)
betraying someone or something -- typically betraying one's own country

(in this context, to betray is to not be loyal--often by helping enemies)
(2) (meaning too rare to warrant focus)