A stopper/piston, in particular made of elastomer, having a cylindrical body having a front axial end that is closed by a front wall. The cylindrical body includes an outside surface provided with at least one sealing profile, the front wall including a front axial outside surface that is provided with a coating, advantageously a film made of ethylene tetrafluoroethylene (ETFE). The front wall includes a sealing profile on its radially-outer edge, the front axial outside surface of the front wall including a deformation profile that is arranged radially inside the sealing profile of the front wall. The deformation profile is adapted to deform radially so as to make it easier to insert and/or to slide said stopper/piston into a syringe body.
