Aretifism

Aretifism is a sexual attraction to people who are not wearing footwear. While such people are necessarily barefoot (or possibly wearing tights or stockings), the attraction is not to the foot as such (which would be foot fetishism) but to its naked vulnerability.

Historically, lack of shoes was often associated with submission before authority, and with servants and slaves, and so aretifism is often associated with the D/s aspect of BDSM.