故交

gùjiāo
  1. former acquaintance
  2. old friend

CEDICT

  1. (literary) old friend
  2. old friend

Wiktionary

舊友。《儒林外史．第八回》：「他雖犯罪朝廷，卻與我是個故交。」也作「故舊」、「故知」。

重編國語辭典

Entry Composition

1 故 gù
  1. happening
  2. instance
  3. reason
  4. cause
  5. intentional
  6. former
  7. old
  8. friend
  9. therefore
  10. hence
  11. (of people) to die, dead
2 交 jiāo
  1. to hand over; to deliver; to pay (money); to turn over
  2. to make friends
  3. (of lines) to intersect
  4. variant of 跤 jiāo

Related entries

舊識 jiùshí
  1. former acquaintance
  2. old friend
舊交 jiùjiāo
  1. old friend
  2. former acquaintance
舊故 jiùgù
  1. old friend
  2. former acquaintance
故人 gùrén
  1. old friend
  2. the deceased
故友 gùyǒu
  1. old friend
  2. deceased friend
老友 lǎoyǒu
  1. old friend
  2. sb who passed the county level imperial exam (in Ming dynasty)
老朋友 lǎopéngyou
  1. old friend
  2. (slang) period
  3. menstruation
我们是老朋友了。

We're friends from way back.

We're old friends.

Source: Tatoeba

舊友 jiùyǒu old friend
雅故 yǎgù
  1. old friend
  2. correct interpretation
世伯 shìbó
  1. uncle (affectionate name for a friend older than one's father)
  2. old friend