Long (of time); having passed a long time. Indicates something hasn't happened for a while or has lasted for a long time.
久しい友人と再会して話が弾んだ。
I met an old friend after a long time and we had a lively conversation.
久しく会っていないので元気か心配だ。
I haven't seen them in a long time, so I'm worried if they're well.
久しい歴史を持つ寺院だ。
It's a temple with a long history.