Part of leg mishit ball (5)
I believe the answer is:
shank
I believe this is a double definition.
'part of leg' is the first definition.
(I know this)
'mishit ball' is the second definition.
(type of mishit shot in tennis)
(Other definitions for shank that I've seen before include "Cut of meat; leg" , "Cut of meat from lower part of foreleg" , "The shin" , "If red, flyer" .)