You are describing a recip ignore. You both can’t see each other’s posts.
A block is what I’ve described. Somebody on here has blocked me. They can’t see my posts. I CAN see theirs, but can’t reply. And there’s a giant warning above every single one of their posts telling me that they’ve blocked me.
Then there’s normal ignores.
There’s also forced ignores that function like the last one, but it’s not optional anymore.
I think? Who knows.