lewdness, licentiousness
婬 centers on excessive, unrestrained desire, especially in a sexual sense: lewdness and licentiousness.
婬 combines 女 (woman) with a phonetic component that also appears in 淫. The right side likely contributes the sound イン and carries a sense of excess or soaking, giving the idea of excessive desire.
A woman 女 beside a shape that suggests excess: imagine a person drowning in desire, unable to control their impulses.
For イン, picture an inn where lewd behavior runs unchecked: inn -> イン, and the scene inside is licentious.