Aide spoiled concept (4)
I believe the answer is:
idea
'concept' is the definition.
(I've seen this before)
'aide spoiled' is the wordplay.
'spoiled' indicates an anagram.
'aide' with letters rearranged gives 'IDEA'.
(Other definitions for idea that I've seen before include "It comes to mind" , "Notion in the mind" , "Mental impression" , "Theory" , "Notion, concept" .)