The ornamental design for an exteriorlight, as shown and described.
FIG. 1 is a perspective view showing the ornamental design of an exterior light according to the invention;
FIG. 2 is a side view showing the ornamental design of the present invention;
FIG. 3 is a front view of the ornamental design of the present invention; and,
FIG. 4 is a back view showing the ornamental design of the present invention. The dashed concentric circles and shapes associated therewith in FIG. 4 do not constitute a part of the claimed ornamental design.