When something is irrevocable, it cannot be changed, undone, or taken back. Once an irrevocable decision is made, you're committed to it permanently, no matter what happens later.

Think of writing your name in wet concrete. While the concrete is still soft, you can smooth it out and start over. But once it hardens, your mark becomes irrevocable: it's there to stay. In the same way, some choices create permanent consequences. When a judge makes an irrevocable ruling, it is meant to stand permanently. When someone makes an irrevocable promise, they can't break it or take it back later.

Words can sometimes feel irrevocable: even if you apologize later, you can't unsay them or erase the memory. Before a company destroys an old building, it considers whether that loss would be irrevocable: once demolished, that piece of history is gone forever.