The ornamental design for an outermirror for a motor vehicle, as shown and described.
FIG. 1 is a perspective view of an outer mirror for a motor vehicle of our new design;
FIG. 2 is a front view of our new design;
FIG. 3 is a rear view of our new design;
FIG. 4 is a top plan view of our new design;
FIG. 5 is a bottom view of our new design;
FIG. 6 is a left-side view of our new design; and,
FIG. 7 is a right-side view of our new design.
Our design includes the mirror image of the embodiment depicted. As used herein, right and left refer to the orientation of the design depicted in the figures above, not the right and left sides of the design as mounted on a motor vehicle.