Gymnophilia is a sexual fetish for nudity whether it be seeing others nude, being nude, or both.
More About Gymnophilia
It’s not unusual for people to become sexually aroused when naked or seeing others that way. Those with gymnophilia are more likely to take it to the extreme or be overly preoccupied with nudity. It can also go hand in hand with things like nudism, naturism, exhibitionism, and voyeurism.