uk ​ /ˈtɪr.ən.i/ us ​ /ˈtɪr.ən.i/. › government by a ruler or small group of people who have unlimited power over the people in their country or state and use it unfairly and cruelly: This, the president promised us, was a war against tyranny. › a situation in which someone or something controls how you are able to live, in an unfair way: Women, the play seems to suggest, must resist the tyranny of domesticity. Thesaurus: synonyms and related words.