Decoration somehow made large (5)
I believe the answer is:
medal
'decoration' is the definition.
(I know that decoration can be written as medal)
'somehow made large' is the wordplay.
'somehow' indicates anagramming the letters.
'large' becomes 'L' (eg in clothes sizes).
'made' with letters rearranged gives 'meda'.
'meda'+'l'='MEDAL'
(Other definitions for medal that I've seen before include "Commemorative piece of metal" , "Prize disc for as for Olympic Games win" , "Coin-like reward for merit" , "Olympic award" , "Award for service" .)