The ornamental design for a plasticbroadheadarrowhead, as shown and described.
FIG. 1 is a front perspective view of the plastic broadhead arrowhead according to the present invention.
FIG. 2 is a top plan view thereof.
FIG. 3 is a bottom plan view thereof.
FIG. 4 is a left side elevational view thereof.
FIG. 5 is a front elevational view thereof; and,
FIG. 6 is a rear elevational view thereof.
The broken lines showing threading in FIGS. 1-4 and the surface within the broken line circle in FIG. 6 are included to illustrate portions of the article and form no part of the claimed design.