Hit on the head for a piece of silver (5)
I believe the answer is:
crown
This clue is a double definition.
'hit on the head' is the first definition.
(I've seen this before)
'piece of silver' is the second definition.
(thesaurus)
'for a' acts as a link.
(Other definitions for crown that I've seen before include "Old coin; top of tree" , "Symbol of monarchy" , "Visible part of a tooth" , "Diadem" , "Top of the head; coin" .)