Illuminating comment (6)
I believe the answer is:
apercu
'illuminating comment' is the definition.
(I've seen this before)
This is the entire clue.
(Other definitions for apercu that I've seen before include "Illuminating or entertaining point (from French)" , "9 [WHATS THE POINT]" , "Entertaining comment" , "insightful comment" , "brief explanation" .)