British soldier dismissing Military Medal as trifle (3)
I believe the answer is:
toy
'trifle' is the definition.
(I've seen this before)
'british soldier dismissing military medal' is the wordplay.
'british soldier' becomes 'tommy' (I've seen this before).
'dismissing' is a deletion indicator.
'military medal' becomes 'mm'.
'tommy' with 'mm' taken out is 'TOY'.
'as' acts as a link.
(Other definitions for toy that I've seen before include "A child's plaything" , "Child's amusement" , "Doll or teddy, say" , "Miniature (dog)" , "Object for a child to play with" .)