In the Dead Tube manga, a girl is being accused of being a 痴女【ちじょ】, at which she replies:
What's the difference between the two words? Is 変態 just a pervert and 痴女 someone that actually sexually assaults people?
変態 are people with abnormal sexual preferences. They can be men or women. 痴女(women) or 痴漢(men) are people who have committed sexual crimes. So, she can be 変態 and not a 痴女 if she has abnormal sexual preferences but does not act on them. Japanese wiki explains this.
To me, when I use 痴女(women) or 痴漢(men), I am not saying if their sexual preferences are abnormal or not but I am saying that they are doing something sexual in abnormal manners, meaning criminal manners.