Hurry up! Agitated shark in swimming pool (4,5)
I believe the answer is:
look sharp
'hurry up' is the definition.
(I've seen this before)
'agitated shark in swimming pool' is the wordplay.
'agitated' is an anagram indicator.
'in' is an insertion indicator.
'swimming' is an anagram indicator (letters swim around into a new order).
'shark' is an anagram of 'kshar'.
'pool' anagrammed gives 'loop'.
'kshar' going into 'loop' is 'LOOK SHARP'.
(Other definitions for look sharp that I've seen before include "step on it" , "Get cracking" , "keen" , "Be quick!" , "Get a move on" .)