evil nature; licentiousness; lewdness
Refers to a person's inherently wicked or morally corrupt character, often with a connotation of sexual depravity. Somewhat literary or formal.
His evil nature troubled those around him from a young age.
The characters in that novel are full of licentiousness.
Compound of 悪 (aku, 'evil') and 性 (shō, 'nature'). The reading しょう for 性 is a go-on reading, often used in Buddhist or classical contexts, giving the word a somewhat formal or literary feel.