Brainwave: Everyman had meal but not sides (4)
I believe the answer is:
idea
'brainwave' is the definition.
(I've seen this before)
'everyman had meal but not sides' is the wordplay.
I cannot quite see how this works, but
'everyman' could be 'i' (where the crossword setter is 'Everyman') and 'i' is found in the answer.
'had' could be 'd' (I've seen this in other clues) and 'd' is present in the answer.
The remaining letters 'ea' is a valid word which might be clued in a way I don't see.
This may be the basis of the clue (or it may be nonsense).
Can you help me to learn more?
(Other definitions for idea that I've seen before include "Purpose" , "Plan" , "Suggestion" , "Notion, concept" , "Flash of inspiration?" .)