Functionally Nude

Functionally nude subjects are those who are wearing a decent amount of clothing, but their main sexual regions (i.e. the breasts and pussy, and occasionally ass) are left exposed.

The nudity is functional because they are only nude enough to function in during sex

Daryl: You seemed to be ploughing Jessica behind the counter at the bar last night but she was wearing clothes?
Jake: Oh, yeah, She was only Functionally Nude