Sole, single, or solo—acting or existing alone rather than with others.
彼は単独で海外に渡り、事業を始めた。
He went abroad alone and started a business by himself.
単独行動はリスクが高い場合がある。
Solo actions can sometimes be risky.
単独インタビューが雑誌に掲載された。
A solo interview was published in the magazine.
Independence or singleness; being independent or singular in character.
その国は単独で政策を決めることを選んだ。
The country chose to decide its policy independently.
単独の判断で事を進めるのは難しい場面もある。
There are situations where it's difficult to proceed on a sole decision.