expression, noun
a long time ago; long since
Rare emphatic expression meaning something happened or was the case a very long time ago, often with a nuance of 'already' or 'long since'. Used in colloquial or literary contexts.
とっくのとうに諦めていた夢だった。
It was a dream I had given up on a long time ago.
その話なら、とっくのとうに知っているよ。
If it's that story, I've known about it for ages.