Synonyms for Tyranny (same or very similar meaning)
WordNet sense 1 (dominance through threat of punishment and violence):
absolutism, despotism
WordNet sense 2 (a form of government in which the ruler is an absolute dictator (not restricted by a constitution or laws or opposition etc.)):
authoritarianism, dictatorship, shogunate, totalitarianism, monocracy, Caesarism, Stalinism, one-man rule
From the ODE community, based on WordNet
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