Marauder one up for covering area (6)
I believe the answer is:
raider
'marauder' is the definition.
(I've seen this before)
I don't understand how the rest of the clue works.
Can you help me to learn more?
(Other definitions for raider that I've seen before include "Marauder" , "Pillager, plunderer" , "person taking food from larder" , "One making incursion" , "looter" .)