Hair clipper

1. 1The ornamental design for a hair clipper, as shown and described.

FIG. 1 is a perspective view of a hair clipper showing my new design;
FIG. 2 is a perspective view thereof from another angle;
FIG. 3 is a front elevational view thereof;
FIG. 4 is a rear elevational view thereof;
FIG. 5 is a left side elevational view thereof;
FIG. 6 is a right side elevational view thereof;
FIG. 7 is a top plan view thereof;
FIG. 8 is a bottom plan view thereof;
FIG. 9 is an enlarged view of the portion indicated by numeral 9 in FIG. 1;
FIG. 10 is an enlarged view of the portion indicated by numeral 10 in FIG. 1; and,
FIG. 11 is an enlarged view of the portion indicated by numeral 11 in FIG. 2.
The broken lines in the drawings show portions of the hair clipper that form no part of the claimed design.
The dot dash dot broken lines depict the boundaries of the detail areas and form no part of the claimed design.