Violent tirade involving a politician (7)
I believe the answer is:
rampant
'violent' is the definition.
(thesaurus)
'tirade involving a politician' is the wordplay.
'tirade' becomes 'rant' (both can mean an angry outburst).
'involving' indicates putting letters inside.
'politician' becomes 'MP' (Member of Parliament).
'a'+'mp'='amp'
'rant' going around 'amp' is 'RAMPANT'.
(Other definitions for rampant that I've seen before include "Uncontrolled" , "Unchecked - standing up on hind legs" , "On the rampage" , "Rife" , "Unrestrained, flourishing excessively" .)