noun
external threat; foreign menace
Refers to threats or pressure from outside a country, often used in political or historical contexts. Commonly appears in the set phrase 内憂外患 (ないゆうがいかん, 'troubles at home and abroad').
当時の日本は外患に悩まされていた。
Japan at that time was troubled by external threats.
内憂外患の時代に、国は大きな決断を迫られた。
In an era of troubles both at home and abroad, the nation was forced to make major decisions.