g-string (or fig leaf or loincloth or any item which covers just the genitals) n. cache-sexe

[French; lit. hide-sex.] [In Key West, Florida] debate rages over whether Fantasy Fest, a long-running Bacchanal in which revelers parade down Duval Street in nothing but body paint, should require nipple-pasties and cache-sexes. (Marc Mewshaw, “Seeking the Key West of Yore,” The Boston Globe, 04/13/2014.)

This word can also be a synonym for fig leaf or loincloth.