Forever
Eternity, Permanence
noun, な adjective, の adjective
An eternity that is far away is not really an eternity, it just feels like it. It's forever, but not the real kind of forever that's actually forever. That's 永久, which is a real forever, this is more like "whoa, I haven't eaten sushi in forever" (actually, you have).
This is a jukugo word that uses the on'yomi readings of the kanji. You should be able to read this on your own.
キッチンタイマーが鳴るのを待つのって、かなり永遠な感じがするよね。
Waiting for the kitchen timer to go off feels like forever, doesn't it?
もう永遠に日本には帰ってこないの？
Won't you ever come back to Japan again?
ある魔女の魔法で、この国には永遠の冬がもたらされたんだけど、魔女はその鍋に永遠に封印されていてね。魔女を解き放たない限りは、四季は取り戻せないんだ。
A witch's magic has brought eternal winter to this country, but she's been permanently sealed in that pot. Unless we release the witch, we can't bring the four seasons back.