This is a fun word to say. I found it in “Pinkeye’s New Year Resolution” in The Complete Casebook of Herlock Sholmes. From the context, I thought it might mean courage, maybe even stupid courage, and I was not far off the true definition. There are some modern terms one could use, but they are vulgar and (in my opinion) distasteful. Why not use a nice word like temerity instead?
Temerity – reckless boldness, rashness
Usage: “Information at my disposal leads me to the conclusion that he has rented an office in the wing of a large building, owned by the Limehouse Trust, Limited. Moreover, he has had the temerity to put his real name on the door.”