The ornamental design for a syringeplunger, as shown and described.
FIG. 1 is a top perspective view of a syringe plunger in accordance with the present invention.
FIG. 2 is a front elevation view thereof;
FIG. 3 is a rear elevation view thereof;
FIG. 4 is a top plan view thereof;
FIG. 5 is a bottom plan view thereof;
FIG. 6 is a right-side elevation view thereof; and,
FIG. 7 is a left-side elevation view thereof.
Portions of the syringe plunger shown in dashed lines in FIG. 1 and FIG. 4 depict unclaimed portions of the syringe plunger that are included for environmental purposes only.