I claim the ornamental design for a clipper, as shown and described.
FIG. 1 is a top and left side perspective view of a nail clipper, embodying a first design;
FIG. 2 is a front elevation view thereof;
FIG. 3 is a rear elevation view thereof;
FIG. 4 is a first side elevation view thereof;
FIG. 5 is a second side elevation view thereof;
FIG. 6 is a top plan view thereof; and,
FIG. 7 is a bottom plan view thereof.
The broken lines that connect the solid contour lines illustrate the bounds of the claim and form no part thereof. The remaining broken lines illustrate indicia and portions of the clipper that form no part of the claimed design.