Wild rave a politician's caught in (7)
I believe the answer is:
'wild' is the definition.
(I've seen this before)
'rave a politician's caught in' is the wordplay.
'rave' becomes 'rant' ('rant' can be a synonym of 'rave').
'politician' becomes 'mp'.
'caught in' indicates putting letters inside.
'rant' enclosing 'amp' is 'RAMPANT'.
(Other definitions for rampant that I've seen before include "Showing unchecked growth" , "Unchecked (and violent?)" , "Unrestrained, as animal may be in heraldry" , "Flourishing excessively as disease may be" , "Rife" .)