How to say "regression" in Japanese

• 回帰かいきCommon
  noun, suru verb, intransitive verbThe technical term for regression, used chiefly in statistics and data analysis. It is not the everyday word for slipping back into a worse state.
• 後戻りあともどりCommon
  noun, suru verb, intransitive verbRegression as going back — literally turning back on a route, or figuratively slipping back into a worse state. It fits a relapse or the loss of progress already made.
• 退化たいかJLPT N1approx.Common
  noun, suru verb, intransitive verbRegression as degeneration or deterioration: a slide into a worse or more primitive state, as of a society. It is not the word for statistical regression.

Use 回帰 for the technical sense found in statistics; 「後戻り」 for going back or relapsing into a worse state; and 退化 for regression as degeneration or deterioration, as of a society.

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

• 退縮たいしゅくregression (of cancer)
• 退行たいこうretrogression
• 退嬰たいえいconservativeness
• リグレッション(software) regression
• デグレ(software) regression
• デグレード(software) regression
• リグレ(software) regression
• 回帰かいきregression
• 後戻りあともどりregression
• 退化たいかregression (e.g. of society)