Quick incursion by the police to arrest first of perpetrators (5)
I believe the answer is:
rapid
'quick' is the definition.
(synonyms)
I don't understand the rest of the clue.
Can you help me to learn more?
(Other definitions for rapid that I've seen before include "Electrical connector" , "Speedy (5)" , "Moving at speed" , "Prompt" , "Fast, speedy" .)