kneecap
Concise Oxford English Dictionary © 2008 Oxford University Press:
kneecap/ˈniːkap/
▶noun the convex bone in front of the knee joint; the patella. ▶verb (kneecaps, kneecapping, kneecapped) shoot (someone) in the knee or leg as a punishment.
'kneecap' also found in these Oxford entries:

