Summarise (briefly) (5)
I believe the answer is:
recap
'summarise briefly' is the definition.
(I've seen this before)
This is all the clue.
(Other definitions for recap that I've seen before include "look back on past things" , "Sum up what has been said" , "Go back over the main points" , "Summary (abbr.)" , "Go over study material again" .)