I claim the ornamental design for a hookah, as shown and described.
FIG. 1 is a perspective view of a hookah, showing my new design;
FIG. 2 is another perspective view of thereof;
FIG. 3 is another perspective view of thereof;
FIG. 4 is another perspective view of thereof;
FIG. 5 is a front elevation view thereof;
FIG. 6 is a rear elevation view thereof;
FIG. 7 is a left side elevation view thereof;
FIG. 8 is a right side elevation view thereof; and,
FIG. 9 is a top plan view thereof.
The part of the photograph shown in a coarser dot pattern within the broken-line perimeter, as well as the broken-line perimeter itself, illustrates a portion of the hookah that forms no part of the claimed design.