A thin garment closure includes a male member with a bar having a ball on at least one end and a female member having a trough shaped complementary to the bar. The bar is positionable in the trough when the male and female members in a substantially transverse orientation, and when one member is rotated so that both members are substantially coplanar the closure is closed. The male and female members each have a flat surface which contacts the flat surface of the mating member when the closure is closed, enabling a thin and narrow closure. In an embodiment, the trough has sidewalls which guide the bar into position in the trough for improved manipulation of the closure. In another embodiment, a detent resists decoupling of the closure while allowing coupling over a range of insertion angles.