Bolthole

This refers to either:

1. A means of quick escape (a “hole” through which a human or animal can “bolt”)
2. A hidden refuge

I’m not sure if the correct spelling has a hyphen. I’ve seen it both ways.

Why I Looked It Up

In The Traitor, they referred to a small London apartment owned by a gangster as a “bolthole.”

Postscript

From Messy: The Power of Disorder to Transform Our Lives:

No wonder Jerome Wiesner, MIT’s president, felt trapped by the magisterial perfection of his office, and kept a messy bolt-hole in Building 20.