How to say "unfair" in Japanese

• 不当ふとうJLPT N1approx.Common
  na-adjective, nounCovers unfair in the sense of unjust or wrongful: treatment, decisions or demands that violate what is right. It frames the matter as an objective injustice rather than a personal complaint.
  その女性じょせいは不当ふとうに私を責せめた。↗

  That woman has wrongly accused me.
• アンフェアCommon
  na-adjectiveThe loanword, essentially English 'unfair' in katakana; it keeps a foreign flavor and is at home in sports and media talk about plays, calls or treatment that are not fair.
• 姑息こそくCommon
  na-adjective, nounColloquially, unfair in the sense of underhanded: winning by sneaky, evasive means instead of facing things openly. It condemns the method as sneaky rather than the outcome as unjust.
  実じつは、大量たいりょうの資料しりょうを持もってくるのは、反論はんろんさせないための姑息こそくな手段しゅだんである。↗

  Actually that I bring a huge volume of reference material with me is a makeshift way of preventing people from disputing my case.
• ずるいJLPT N2approx.Common
  i-adjectiveUse it when unfair means sneaky or cheating: someone dodges the rules, tricks you or takes an advantage. As an exclamation it amounts to 'That's not fair!'.
  狐きつねは他たのどんな動物どうぶつよりもずるいということだ。↗

  It is said that the fox is more cunning than any other animal.
• 酷こくCommon
  na-adjective, nounReally means severe or harsh; it overlaps with unfair only when a judgment or demand is harsh or hard on someone rather than unjust. For plain unfairness it is seldom the word you want.

Choose 不当 for unfairness that is objectively unjust or wrongful, 「アンフェア」 as the loanword for a general 'not fair', 姑息 for underhanded methods, 「ずるい」 for sneaky cheating, and 酷 only when unfair means harsh.

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

• 不当ふとうunfair
• アンフェアunfair
• 姑息こそくunderhanded
• ずるいsly
• 酷こくsevere
• 不穏当ふおんとうimproper
• 汚らわしいけがらわしいfilthy
• 片手落ちかたておちone-sided
• 不適正ふてきせいimproper
• ずっこいsly
• 卑怯ひきょうunfair
• 卑しいいやしいvulgar
• 不明朗ふめいろうquestionable
• ひどいexcessive