Spat, extremely prevalent conflict (6)
I believe the answer is:
strife
'conflict' is the definition.
(I've seen this before)
'spat extremely prevalent' is the wordplay.
'extremely' suggests removing the centre.
'prevalent' becomes 'rife' ('rife' can be a synonym of 'prevalent').
'spat' with its centre taken out is 'st'.
'st'+'rife'='STRIFE'
(Other definitions for strife that I've seen before include "Refits (anag)" , "Conflict, quarrelling" , "Conflict, dissension" , "Trouble and discord" , "Discord and friction" .)