Claps wildly when there's a trophy (5)
I believe the answer is:
scalp
'there's a trophy' is the definition.
(I've seen this before)
'claps wildly' is the wordplay.
'wildly' indicates an anagram.
'claps' with letters rearranged gives 'SCALP'.
'when' acts as a link.
(Other definitions for scalp that I've seen before include "wants to resell theatre tickets" , "Cut hair very short" , "Skin covering top of the head" , "Hirsute war trophy once taken by Native Americans" , "Skin with hair as trophy" .)