nefarious – adjective – flagrantly wicked or impious

https://www.merriam-webster.com/dictionary/nefarious

“… they joyfully rushed into the city to pursue and kill the nefarious enemies, as their comrades were already doing.” (The Crusaders’ Capture of Jerusalem)

This is a passage about the first crusades and how they captured Jerusalem. I knew nefarious meant bad, but I didn’t know it meant wicked or impious.