You searched for: “greave
greave, grieve
greave (GREEV) (noun)
A medieval reference to the piece of armor designed to cover the lower leg: A greave was fastened to each of a knight’s legs with leather straps.
grieve (GREEV) (verb)
To cause distress or sorrow: It will grieve Richard when he has to tell Jane that her employment has been terminated.

A knight wearing medieval armor would tend to grieve if a greave on either of his legs was broken and he was wounded as a result.