The ornamental design for an undergarment for men, as shown and described.
FIG. 1 is a perspective view of an undergarment for men embodying my design;
FIG. 2 is a front view of the undergarment for men;
FIG. 3 is a rear view of the undergarment for men;
FIG. 4 is a right side view of the undergarment for men;
FIG. 5 is a left side view of the undergarment for men;
FIG. 6 is a top view of the undergarment for men; and,
FIG. 7 is a bottom view of the undergarment for men.
The partial human torso shown in broken lines in FIG. 1 illustrates the environment in which the claimed design is used. The broken lines shown along the edge of the waist and on each leg cuff are stitching. The broken lines shown enclosing the interior of the waist in FIGS. 2 and 4 as well as the leg openings in FIG. 5 define the bounds of the claim. None of the broken-line matter forms a part of the claimed design.