The ornamental design for a hairdryer, as shown and described.
FIG. 1 is a top isometric view of a hair dryer in accordance with the present invention, with the cord broken away on the end to indicate indeterminate length;
FIG. 2 is a bottom isometric view thereof;
FIG. 3 is a side view thereof;
FIG. 4 is a side view thereof;
FIG. 5 is a front view thereof;
FIG. 6 is a rear view thereof;
FIG. 7 is a top view thereof; and,
FIG. 8 is a bottom view thereof.
The hair dryer design is characterized by a base, an extension arm assembly, and a hood as shown herein.