筋合い・筋合|すじあいsujiai[0]heiban (flat)

1. nounreason; right

• Synonym理由りゆうNeutralThe most general word for a reason, as in 「遅れた理由」. 「筋合」 is mostly negative — 「〜する筋合いはない」 — about having no grounds or obligation to do something.
• Synonym訳わけCasualCommon in speech for a cause or reason, as in 「訳を話す」. 「わけにはいかない」 says you cannot do something on principle; 「筋合い」 asks whether you have the right or obligation to.
• Synonym理屈りくつNeutralLogic or reasoning, also strained logic as in 「理屈をこねる」; leans toward logical argument. 「筋合」 is about whether there is a legitimate reason to do something.
• Synonym道理どうりNeutralCommon sense or moral reason, as in 「道理に合わない」; leans toward what is generally reasonable. 「筋合」 is mostly negative, denying grounds or obligation to do something.
• Related根拠こんきょWrittenWritten/formal prose: grounds or basis, as in 「根拠のない噂」; leans toward evidence. 「筋合」 is not about evidence but about whether one should do something.
• Related事由じゆうWrittenWritten/formal prose: the reason for something, as in 「解雇事由」; leans toward legal documents. 「筋合」 is for verbally questioning whether someone has grounds to do something.
• Related事情じじょうNeutralCircumstances or the situation behind something, as in 「事情がある」; leans toward concrete conditions. 「筋合」 is about whether there are grounds to do something.
• Related一理いちりWrittenWritten/formal prose: some truth or a valid point, mostly 「一理ある」, expressing partial agreement. 「筋合」 is mostly negative, denying a legitimate reason.
• RelatedいわれWrittenWritten/formal prose: the origin or history behind something, as in 「謂れのない非難」. In the negative it is close to 「筋合はない」 — both deny any legitimate reason.
• Related所以ゆえんWrittenWritten/formal prose: the reason something is what it is, as in 「人の人たる所以」; explains an essence. 「筋合」 questions whether one ought to do something.
• RelatedかどWrittenWritten/formal prose: a matter that becomes the reason, mostly 「〜の廉で逮捕」; leans toward charges or offences. 「筋合」 is not limited to legal contexts.

For causes and reasons use 「理由」 or 「訳」. Use 「筋合い」 for whether one has the grounds, obligation, or standing to do something, often 「あなたに言われる筋合いはない」. For something baseless, say 「謂れのない」.

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

1. ある事柄ことがらが当然とうぜんそうであるべき理由りゆうや根拠こんきょ。