Here is one of my favorite words when it comes to crime novels and mystery stories. Even though I know the meaning of the word, when I found it in “The Case of the Bolshevik!” in The Complete Casebook of Herlock Sholmes, I couldn’t resist adding it to my blog’s dictionary.

Nefarious – extremely wicked or villainous

Usage: “I am perfectly aware that he has had nefarious designs upon the eminent statesmen who meet in conference today.”