Hit with a piece of shrapnel (3)
I believe the answer is:
rap
'hit' is the definition.
(rap can mean to knock or hit)
'piece of shrapnel' is the wordplay.
'piece of' indicates a hidden word.
'RAP' is hidden in the letters of 'shrapnel'.
'with a' is the link.
(Other definitions for rap that I've seen before include "black music is a > blow" , "Sort of music" , "African-American music in which the lyrics are spoken" , "African-American music, the lyrics are chanted" , "talking during musical performance" .)