ous ‧ ter /ˈaʊstə $ -ər/ BrE AmE noun [uncountable] American English
[ Date: 1500-1600 ; Language: Anglo-French ; Origin: ⇨ ↑ oust ]
when someone is removed from a position of power or from a competition – used in news reports
sb’s ouster/the ouster of somebody
the ouster of the brutal dictatorship