Little boy making a plaything out of a medal (5)
I believe the answer is:
tommy
'little boy' is the definition.
'Tommy' can be an answer for 'boy'. I'm not certain of the 'little' bit.
'a plaything out of a medal' is the wordplay.
'a plaything' becomes 'toy' ('toy' can be a synonym of 'plaything').
'out of' is an insertion indicator (some letters on the outside of others).
'a medal' becomes 'MM' (Military Medal).
'toy' going around 'mm' is 'TOMMY'.
'making' acts as a link.
Can you help me to learn more?
(Other definitions for tommy that I've seen before include "British soldier (informal)" , "Doubtful apostle could be so familiar" , "Private soldier (slang)" , "Bread" , "Private in the Army - kind of gun" .)