Everybody's cribbing the day before examination (1,5)
I believe the answer is:
a level
'examination' is the definition.
(I've seen this before)
'everybody's cribbing the day' is the wordplay.
I cannot really see how this works, but
'day' could be 'eve' (eve is a kind of day) and 'eve' is located in the answer.
'everybody' could be 'all' (all people) and 'all' is found within the leftover letters.
No letters remain.
This may be the basis of the clue (or it may be nonsense).
'before' acts as a link.
Can you help me to learn more?
(Other definitions for a level that I've seen before include "School qualification" , "You'd have to take papers for this" , "Advanced exam" , "Final exam for students at secondary school" , "School examination in a single subject" .)