The ornamental design for a swimsuit, as shown and described.
FIG. 1 is a front view of a swimsuit on a model showing the new design according to the present invention.
FIG. 2 is a rear view thereof.
FIG. 3 is a left-side view thereof; and,
FIG. 4 is a right-side view thereof.
The dash-dot-dash lines immediately adjacent to the solid lines illustrating portions of the swimsuit define the bounds of the claimed design and form no part thereof. The broken lines and the dotted surface lines illustrate portions of the swimsuit that form no part of the claimed design. All other broken lines illustrating the body are for environmental purposes only and form no part of the claimed design.