--a cyclist that does not wear a helmet. The
bonehead part of the cyclist refers to:
a) the condition the cyclist will achieved if he/she were to crash and hit his/her head on the road, tearing up some valuable tissue and exposing bone from the
skull;
b) the fact that the cyclist has nothing in their
cranium but bone;
c) the use of
bone to protect the head instead of a helmet;
d) behaviour on a bicycle that exudes idiocy.