How to say "reciprocal" in Japanese

• 相互そうごJLPT N2approx.Common
  no-adjectiveThe everyday word for 'mutual, reciprocal' between two parties, as in reciprocal understanding, trust, or cooperation. This is usually the word you want for relationships and actions going both ways.
  それは相互そうご理解りかいの欠如けつじょがもとになっていると思おもう。↗

  I think that is based on a lack of mutual understanding.
• 逆数ぎゃくすう
  nounThe mathematical reciprocal: the multiplicative inverse of a number, such as the reciprocal of two. Use this only in mathematical contexts, never for reciprocal relations between people.
• 相反性そうはんせい
  na-adjectiveA rare, technical noun suggesting reciprocity in the sense of standing in a mutual or opposing relation. It is seldom the word you want for ordinary uses of 'reciprocal'.
• 相反的そうはんてき
  na-adjectiveA rare, technical adjectival counterpart of 相反性, describing something reciprocal in an abstract or academic sense. For everyday 'reciprocal' meanings, other words are far more natural.
• 互恵的ごけいてき
  na-adjectiveReciprocal in the sense of mutually beneficial: each side gains from the exchange, as in a reciprocal trade or partnership. Choose this when benefit flows to both parties.

Use 相互 for mutual relations, 互恵的 for mutually beneficial exchanges, 逆数 for the mathematical reciprocal, and treat 相反性 and 相反的 as rare, mostly technical choices.

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

• 相互そうごmutual
• 逆数ぎゃくすうreciprocal
• 相反性そうはんせいreciprocal
• 相反的そうはんてきreciprocal
• 互恵的ごけいてきreciprocal