Here is a word that Dr Watson uses regularly to describe the villains in The Greatest Adventures of Sherlock Holmes. In particular, this is how he described Mr Woodley, the abductor, in “The Solitary Cyclist” and Mr Milverton, the blackmailer, in “Charles Augustus Milverton”.
Odious – extremely unpleasant and revulsive
Usage: “That odious man, Mr Woodley.”