知人|ちじんchijin[0]heiban (flat)

1. nounfriend; acquaintance
   もし私の家いえが大だい邸宅ていたくだったら私の誕生日たんじょうびのパーティーには知人ちじんをみんな招待しょうたいするのだが。↗

   If my house were a mansion, I would invite everyone I know to my birthday party.

• Synonym知り合いしりあいNeutralEveryday word for someone you know; common in speech. 「知人」 is more written and formal, typical of news reports and letters.
• Synonym顔見知りかおみしりNeutralSomeone you have met and recognize; the tie stays shallow. 「知人」 is anyone you know, whether the bond is close or distant.
• Synonym知己ちきWrittenWritten/formal prose for someone who deeply understands you; 「知人」 only means an acquaintance, with no nuance of deep understanding.
• Related知音ちいんWrittenWritten word for a bosom friend who truly understands you, from the classic 知音 tale; 「知人」 is a general term for anyone you know, close or not.
• Antonym他人たにんNeutralAnother person, or someone with no tie to you; the opposite of 「知人」 in whether a relationship exists.
• Antonym赤の他人あかのたにんNeutralStresses someone with no connection to you whatsoever, even if you have met; contrasts with 「知人」, a person you actually have dealings with.

In speech, say 「知り合い」 for someone you know; 「知人」 is the written, formal choice seen in news and letters. Use 「顔見知り」 for a familiar face, 「知己」 or 「知音」 for a deep confidant. Opposites: 「他人」, 「赤の他人」.

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

1. お互たがいに知しっている人ひと。知り合しりあい。