noun
uncivilized country; undeveloped nation
Refers to a country perceived as lacking modern civilization or development. Often used in historical or comparative contexts; can carry a judgmental tone.
19世紀のヨーロッパ人は、日本を未開国と見なしていた。
In the 19th century, Europeans regarded Japan as an uncivilized country.
その探検家は未開国を旅して回った。
The explorer traveled around undeveloped countries.
発展途上国 is the standard modern term for a developing nation, without the negative or outdated connotations of 未開国.
Compound of 未開 (mikai, 'uncivilized, unopened') + 国 (koku, 'country'). The exact historical derivation is uncertain, but the word follows a common Sino-Japanese pattern for describing types of nations.