noun
old friend; old pal
Refers to a friend from the past, often someone you haven't seen in a long time. Slightly formal and literary compared to casual alternatives like 昔の友達.
先日、大学時代の旧友と十年ぶりに再会した。
The other day, I reunited with an old friend from my university days for the first time in ten years.
He returned to his hometown to visit an old friend.