noun, noun which may take the genitive case particle 'no'
eventful times for the nation; national turmoil
A somewhat literary or formal expression describing a period when the country faces many serious events or crises. Often used in political commentary or historical descriptions.
In these eventful times for the nation, the government was pressed to respond quickly.
The history book describes it as an era of national turmoil.
多事 alone means 'eventfulness' or 'many affairs', but 国家多事 specifically refers to the nation being in such a state.
国難 means 'national crisis' and is more concrete about a specific danger, while 国家多事 describes a broader period of many events or unrest.
Compound of 国家 (nation) and 多事 (many affairs/eventfulness). The exact historical derivation is uncertain, but the phrase follows classical Chinese-influenced word formation.