also: みつにゅうごく
noun, noun or participle which takes 'suru', intransitive verb
illegal entry into a country; smuggling oneself in
Refers to entering a country without going through official immigration procedures. Often used in news contexts.
彼は密入国で逮捕された。
He was arrested for illegal entry into the country.
密入国者が増えているというニュースを見
I saw a news report that the number of illegal immigrants is increasing.