Flipping greatest English test! (4)
I believe the answer is:
exam
'test' is the definition.
(synonyms)
'flipping greatest english' is the wordplay.
'flipping' is a reversal indicator.
'greatest' becomes 'max' (I can't justify this - if you can you should believe this answer much more).
'english' becomes 'e' (abbreviation).
'max'+'e'='maxe'
'maxe' backwards is 'EXAM'.
Can you help me to learn more?
(Other definitions for exam that I've seen before include "Students sit it" , "Test (abbr)" , "(Academic) test" , "Educational test" , "School test (colloq.)" .)