Pull an all-nighter, say (4)
I believe the answer is:
cram
'pull an all-nighter say' is the definition.
(I've seen this in another clue)
This is the entire clue.
(Other definitions for cram that I've seen before include "Pack in or study hard" , "Quickly learn - stuff" , "prepare for exam" , "Stuff (facts for exam)" , "Study intensively" .)