Inroads (5)
'inroads' is the definition.
(I've seen this in another clue)
This is all the clue.
(Other definitions for raids that I've seen before include "Military incursions, forays" , "Military attacks" , "Invasions" , "Surprise attacks" , "Searches by police without warning" .)
(Another definition for forays that I've seen is " Sudden attacks or raids".)