Translation guide
In Japanese, referring to an 'old acquaintance' depends on the relationship and context. The most common and natural expressions are 昔の知り合い (mukashi no shiriai) for a general former acquaintance, and 古い友人 (furui yūjin) for an old friend. More specific terms like 旧友 (kyūyū) and 旧知 (kyūchi) are used in formal or literary contexts.
Referring to someone you knew in the past, but not necessarily a close friend.
The most common and neutral way to say 'old acquaintance'. It implies someone you knew before but may not be in regular contact with now.
彼は昔の知り合いです。
He is an old acquaintance.
I ran into an old acquaintance on the street.
A somewhat formal term for an old acquaintance, often used in written language or formal speech. It can also imply a long-standing relationship.
彼とは旧知の仲だ。
He and I are old acquaintances.
Referring to a friend from the past with whom you had a close relationship.
A natural way to say 'old friend'. It emphasizes the length of the friendship.
彼は私の古い友人です。
He is an old friend of mine.
A more formal or literary term for an old friend. Often used in writing or speeches.
旧友と再会した。
I reunited with an old friend.
A casual way to say 'old friend', similar to 昔の知り合い but with a stronger implication of friendship.
昔の友達と久しぶりに会った。
I met an old friend for the first time in a while.
Specifically referring to a friend from childhood.
Refers to a childhood friend, someone you've known since you were very young. It carries a sense of deep, long-term familiarity.
彼女は私の幼なじみです。
She is my childhood friend.
A more literal and descriptive way to say 'childhood friend'. It's less idiomatic than 幼なじみ but still natural.
子供の頃の友達と連絡を取っている。
I keep in touch with my childhood friends.
知り合い (shiriai) means 'acquaintance', someone you know but are not necessarily close to. 友人 (yūjin) is a more formal word for 'friend', while 友達 (tomodachi) is the casual, everyday term for 'friend'. When saying 'old acquaintance', 昔の知り合い is the safest choice if the relationship is not clearly a friendship.
The direct translation '古い知り合い' (furui shiriai) is not idiomatic. Use 昔の知り合い instead. '古い' is more often used for objects, not relationships.