旧知
Meanings
1
Refers to a person one has known for a long time, often with a sense of familiarity and trust. Slightly formal/literary tone.
He is an old friend of mine.
Since we're old acquaintances, there's no need to stand on ceremony.
Usage patterns
- 〈人〉と旧知の仲だto be a longtime acquaintance of someone
He and I are old acquaintances.
- 旧知を頼るto rely on an old acquaintance (for help)
When in trouble, all you can do is rely on an old acquaintance.