Frenzied attack stopped by bachelor (5)
I believe the answer is:
rabid
'frenzied' is the definition.
(I've seen this before)
'attack stopped by bachelor' is the wordplay.
'attack' becomes 'raid' (raiding is a kind of attacking).
'stopped by' is an insertion indicator (stopping can mean blocking a gap).
'bachelor' becomes 'B' (abbreviation e.g. BA=Bachelor of Arts).
'raid' enclosing 'b' is 'RABID'.
(Other definitions for rabid that I've seen before include "Violent; hydrophobic" , "Mad like deranged dog" , "Mad; raging" , "Extreme, fanatical" , "Affected by hydrophobia" .)