Rascal half scared by a politician (5)
I believe the answer is:
scamp
'rascal' is the definition.
(synonyms)
'half scared by a politician' is the wordplay.
'half' means to take half the letters.
'by' says to put letters next to each other.
'a politician' becomes 'MP' (Member of Parliament).
'scared' halved is 'sca'.
'sca'+'mp'='SCAMP'
(Other definitions for scamp that I've seen before include "Scallywag" , "Little Devil" , "villain" , "Impish child" , "A young rascal misbehaving in camps" .)