A closure (20, 20A, 20B) for a container (22) with an outwardly projecting flange (25). The closure including a skirt (50, 50A, 50B) for attaching the closure (20, 20A, 20B) to the container (22). The skirt (50, 50A, 50B) has an annular, flexible retention member (66, 66A) extending laterally inwardly from a lower end portion (54, 54A, 54B) of the skirt (50, 50A, 50B) to define a connection (62, 62A, 62B) therebetween. In one form, the flexible retention member (58, 58A, 58B) has (a) an initial, undeflected configuration, (b) a deflected configuration rotated away therefrom about the connection (62, 62A, 62B), and (c) a proximal end surface (126, 126A) located at the connection (62, 62A, 62B) defining a shoulder when the flexible retention member (58, 58A, 58B) is in the undeflected configuration. In another form, the flexible retention member (58, 58A, 58B) is movable into the deflected configuration when subjected to an axial force of between about 100 Newtons and about 150 Newtons.