How to say "autonomous" in Japanese

• 自主的じしゅてきCommon
  na-adjectiveThe common word for 'autonomous' as 'voluntary, of one's own initiative': acting by one's own decision rather than on someone else's instructions. Fits people and groups who plan, decide or act for themselves.
  山火事やまかじの後あとなので今年ことしの花火はなび大会たいかいは自主的じしゅてきに中止ちゅうしを決定けっていしました。↗

  After the bushfires, we have independently decided to call off this year's fireworks display.
• 主動的しゅどうてき
  na-adjectiveLess common and seldom the word you want for 'autonomous': it belongs chiefly to academic and philosophical prose, where it contrasts the active — acting from within — with the passive, rather than describing everyday self-direction.
• 自律的じりつてき
  na-adjectiveCovers 'autonomous' as self-governing or self-regulating: a person, organization or system that directs and sustains itself by internal rules rather than outside control. It stresses internal regulation, not initiative, and also matches 'autonomic' and 'self-directed'.

Choose 自主的 for voluntary, self-initiated action; 自律的 for self-governing or self-regulating people, organizations and systems; treat 主動的 as a less common academic term that is seldom the word you want.

Usage comparisons are AI-assisted and cross-checked by multiple models; for study reference only

• 自主的じしゅてきindependent
• 主動的しゅどうてきautonomous
• 自律的じりつてきautonomous