Furious attack around a bridgehead (5)
I believe the answer is:
rabid
'furious' is the definition.
(thesaurus)
'attack around a bridgehead' is the wordplay.
'attack' becomes 'raid' (raiding is a kind of attacking).
'around' indicates putting letters inside.
'a bridgehead' becomes 'b' (head letter of 'bridge').
'raid' placed around 'b' is 'RABID'.
(Other definitions for rabid that I've seen before include "Extremely fanatical" , "Burning" , "extremist" , "Mad; raging" , "Fanatical like mad dog" .)