n: anything that is kept secret or remains unexplained or unknown
I don’t know what her last email said. I never read it. It shall always remain a mystery. But it didn’t matter. I had accomplished my mission. I had blown up the bridge and now there was no going back. I had destroyed everything sufficiently enough that no amount of apologizing could make things go back to where they were. I had no choice but to move on. I could hear her closing down what little she felt for me in the first place until all the doors were shut firmly. There would be no opening them again. I could either stare and stare at them, locked coldly against me, or I could go off and find some open door elsewhere. Not really much of a choice. So I sighed and walked off, jiggling doorknobs as I went.