Aide made odd impression (4)
I believe the answer is:
idea
'impression' is the definition.
(I've seen this before)
'aide made odd' is the wordplay.
'made odd' indicates an anagram (an unusual or odd ordering of the letters).
'aide' with letters rearranged gives 'IDEA'.
(Other definitions for idea that I've seen before include "Product of the mind" , "Mental impression" , "Notion in the mind" , "Fancy" , "Light bulb above head" .)