Meaning

noun a crime that undermines the offender's government

noun disloyalty by virtue of subversive behavior

noun an act of deliberate betrayal

originFrom Middle English tresoun, treison, from Anglo-Norman treson, from Old French traïson (“treason”), from trair, or from Latin trāditiō (“a giving up, handing over, surrender, delivery, tradition”), from trādō (“give up, hand over, deliver over, betray”, verb), from trāns- (“over, across”) + dō (“give”). Doublet of tradition; also related to betray.

Etymology from Wiktionary, CC BY-SA 3.0