Dismissal repeated quickly (4-4)
I believe the answer is:
chop-chop
'quickly' is the definition.
(I know that quickly can be written as chop-chop)
'dismissal repeated' is the wordplay.
'dismissal' becomes 'chop' (I can't explain this - if you can you should believe this answer much more).
'repeated' says to double the letters.
'chop' doubled is 'CHOP-CHOP'.
Can you help me to learn more?
(Other definitions for chop-chop that I've seen before include "Hurry up!" , "Quickly!" , "Get a move on!" .)