Don't join 'Easter Egg' movement (9)
I believe the answer is:
segregate
'don't join' is the definition.
'easter egg movement' is the wordplay.
'movement' is an anagram indicator.
'easter'+'egg'='easteregg'
'easteregg' with letters rearranged gives 'SEGREGATE'.
(Other definitions for segregate that I've seen before include "Separate by race or religion" , "Easter-egg (anag.)" , "Isolate with Easter Egg" , "Isolate, separate" , "Cut off" .)