Aide made unusual scheme (4)
I believe the answer is:
idea
'scheme' is the definition.
(I've seen this in another clue)
'aide made unusual' is the wordplay.
'made unusual' indicates an anagram.
'aide' with letters rearranged gives 'IDEA'.
(Other definitions for idea that I've seen before include "Thought; concept" , "intellectual product" , "Notion, concept" , "Clue" , "It comes to mind" .)