Long Ago
For a Long Time
い adjective
This is a single kanji with しい on the end, meaning it's an adjective. What's the adjective form of long time? Well, it's long ago, or can mean for a long time.
Since this word consists of a kanji with hiragana attached, you can bet that it will use the kun'yomi reading. You didn't learn that reading with this kanji, so here's a mnemonic to help you:
Long ago, in a galaxy far away, a bunch of prequel movies were ruined by a single character. "Heesa (ひさ) the best character!" you hear. Oh no. Heesa here. Get out before Jar Jar Binks gets you! Keep him in the past!
わたしがベーコンをたべなくなって久しい。
It’s been long since I stopped eating bacon.
へいわボケして久しい日本人には、おそらくりかいできないだろう。
Japanese people have taken peace for granted for so long that they probably can't understand it anymore.
かれが生のきんぎょをたべてしんでから久しい。
He ate a raw goldfish and has been dead for a long time now.