"... you know the rest" (3)
I believe the answer is:
etc
'you know the rest' is the definition.
(I've seen this in another clue)
This is the entire clue.
(Other definitions for etc that I've seen before include "And so forth (abbr)" , "And so on, briefly" , "'And the rest, in short (3)'" , "And so on, in brief" , "Etcetera (abbrev.)" .)