DEFRA's head argued about number getting flooded (7)
I believe the answer is:
drowned
'flooded' is the definition.
(thesaurus)
'defra's head argued about number' is the wordplay.
'head' says to take the initial letters.
'argued' becomes 'rowed' (I've seen this before).
'about' indicates putting letters inside.
'number' becomes 'n' (n can represent any number).
The first letter of 'defra' is 'd'.
'rowed' going around 'n' is 'rowned'.
'd'+'rowned'='DROWNED'
'getting' is the link.
(Other definitions for drowned that I've seen before include "Lost at sea" , "Died by submersion" , "Submerged, flooded" , "Died underwater" , "Suffocated in water" .)