Windscreen wiper adapter with safety position

The invention relates to an adapter (9) for connecting a windscreen wiper blade (1) to a drive arm (3) of a wiper system, said adapter (9) being configured to be connected to a connector (8) with a degree of freedom in pivoting about an axis of articulation, said connector (8) being fixed to the blade (1), said adapter (9) comprising means for keeping in a nominal position of immobilization on the arm, said adapter (9) being configured to be immobilized, in a direction known as the direction of retraction, situated in a plane perpendicular to the axis of articulation, in a safety position, should said retaining means (20) fail. According to the invention, the adapter (9) is configured to be guided by the arm (3) in a translational movement, in said direction of retraction, from said nominal position to said safety position and/or to have a direction of deliberate disengagement from the arm starting from a position located between the two, nominal and safety positions. The invention also relates to an attachment device and to a wiper system comprising such an adapter.