Defilement is a term for the act of polluting, damaging, or otherwise violating a fetish object, an intimate partner, or oneself for sexual arousal or gratification. The arousal that stems from defilement is known as anophelorastia.
When an interest in defilement becomes a fetish, it is known as salirophilia. People with this fetish are known as salirophiles.
In a legal context. defilement refers to performing an unlawful sexual act on a child.
Defilement is also known more specifically as sexual defilement.