Raid carried out in the absence of water (4)
I believe the answer is:
arid
'raid' is the definition.
(I have seen 'Dry raid ' mean 'arid' so perhaps 'raid' could also mean 'arid')
I can't explain the remainder of the clue.
Can you help me to learn more?
(Other definitions for arid that I've seen before include "Dry and withered" , "(Of land) very dry" , "flat" , "Dry and parched, as with regions" , "Tedious; short of rain" .)