What is the Latin word for treason?

The usual Latin words for “treason” are prōditiō, perduelliō, scelus; also laedō. The right choice depends on the sense; see the distinctions below.

English → Latin

“treason” in Latin

prōditiōdiscovery, betrayal, treason; appearance (coming or going); putting off, deferring perduelliōtreason scelusan evil deed; a wicked, heinous, or impious action; wickedness, villainy; criminal, villain, felon, scoundrel, rascal, r laedōto strike, collide, hurt; to offend; to thwart

The English word treason itself goes back to Latin dō, through trāditiō.

Riddle & Arnold A Copious and Critical English–Latin Lexicon, 1864

treason

proditio (treachery). High treason, perduellio (the crime of one who undertakes anything against the freedom of the citizens and the public safety); crimen majestatis, or (in later writers) crimen laesae majestatis (the offence of one who wrongs the dignity and disturbs the tranquillity of the Roman people and the government; as, by betraying an army to the enemy, by sedition, etc; Vid: Tac., Ann., 1, 72, 2: in later times, an offence against the sacred person of the prince; ☞ Johann Gottlieb Heineccius, Antiquitatum Romanarum jurisprudentiam illustrantium syntagma, 4, 18, 46, and the followings. In the time of the republic, the Romans, especially the orators, expressed “high treason” against the state by paricidium patriae, or by the more general term, scelus; both opposed to pietas; Vid: Cic., Sull., 2, 6; Off., 3, 21, 83; Cat., 2, 1, 1; 11, 25): to commit or be guilty of high treason (agist the Roman people), majestatem populi Romani minuere or laedere: to commit treason against one’s native country, patriae paricidio obstringi or se obstringere: to declare anything to be treason against the state, indicare aliquid contra rempublicam factum esse.

Quick answer

What is the Latin word for treason?: The usual Latin words for “treason” are prōditiō, perduelliō, scelus; also laedō. The right choice depends on the sense; see the distinctions below.

Entry from J. E. Riddle & T. K. Arnold, A Copious and Critical English–Latin Lexicon (rev. C. Anthon, New York: Harper, 1864), digitised by Fergus J. P. Walsh, CC BY-SA 4.0; Latin markup adapted by latindictionary.co.