The ornamental design for an applicator, as shown and described.
FIG. 1 is a top, front, right perspective view of an applicator showing my new design;
FIG. 2 is a front view thereof;
FIG. 3 is a rear view thereof;
FIG. 4 is a right side view thereof;
FIG. 5 is a left side view thereof; and,
FIG. 6 is a top view thereof.
The uneven-length broken lines represent unclaimed boundaries of the claimed design. The even-length broken lines showing the remainder of the applicator are for environmental purposes only and form no part of the claimed design.