Arid sort of attack (4)
I believe the answer is:
raid
'attack' is the definition.
(I know that raid is a type of incursion)
'arid sort' is the wordplay.
'sort' is an anagram indicator.
'arid' with letters rearranged gives 'RAID'.
'of' acts as a link.
(Other definitions for raid that I've seen before include "Finch and Bronson starred in . . . . On Entebbe" , "Stock Exchange activity" , "Sally" , "Invade" , "Smash-and-grab?" .)