1: having, showing, or arising from intense often vicious ill will, spite, or hatred.
2: productive of harm or evil.
[Origin: Latin malevolent-, malevolens, from male badly + volent-, volens, present participle of velle to wish.]
“He had a vision of that lone velvety ear, fluttering like a huge malevolent moth through the attics at the Schloss.” – Wash This Blood Clean From My Hand, Fred Vargas.
One of my favourites. Right next to malignant and malice.
Yes, the letter M gets some of the best. I quite like Mayhem.