Illustration needs a little help, Max Ernst reflected (7)
I believe the answer is:
example
'illustration' is the definition.
(I know that illustration can be written as example)
'a little help max ernst reflected' is the wordplay.
'a little' indicates a hidden word (a little bit of the clue).
'reflected' says the letters should be written backwards (letters reflected back).
'elpmaxe' can be found hidden inside 'help max ernst'.
'elpmaxe' back-to-front is 'EXAMPLE'.
'needs' acts as a link.
(Other definitions for example that I've seen before include "Characteristic item" , "Ideal - specimen" , "not the actual version" , "Thing illustrating a general rule" , "Instance or illustration" .)