say it: TREE-zuhn
treason is a noun meaning "a crime that undermines the offender's government". It carries 3 recorded senses.
a crime that undermines the offender's government
disloyalty by virtue of subversive behavior
an act of deliberate betrayal
Forms marked · are formed by the regular rule rather than recorded in the source data. English keeps a few hundred irregulars and the rest follow the pattern, so the rule is right far more often than not — but it is a rule, and the mark says so.
Definitions, synonyms and semantic relations for treason come from Princeton University’s WordNet. The pronunciation comes from the CMU Pronouncing Dictionary. Commonness is measured against a corpus of everyday English. Full sources and licences.