'Impurity' in the Bible

For this reason, God delivered them to sexual impurity as they followed the lusts of their hearts and dishonored their bodies with one another.

I am speaking in simple terms because of the frailty of your human nature. Just as you once offered the parts of your body as slaves to impurity and to greater and greater disobedience, so now, in the same way, you must offer the parts of your body as slaves to righteousness that leads to sanctification.