The gunners wildly mob this character (5)
I believe the answer is:
rambo
'character' is the definition.
I don't know anything about this answer so I cannot tell whether this works.
'the gunners wildly mob' is the wordplay.
'the gunners' becomes 'RA' (Royal Artillery).
'wildly' indicates an anagram.
'mob' with letters rearranged gives 'mbo'.
'ra'+'mbo'='RAMBO'
'this' acts as a link.
Can you help me to learn more?
(Other definitions for rambo that I've seen before include "Brainless hero" , "Tough man (films)" , "Character relying on brute force" , "Sly feature" , "Tough film hero" .)