Small firm under review by Liberal rascal (9)
I believe the answer is:
scoundrel
'rascal' is the definition.
(I've seen this before)
'small firm under review by liberal' is the wordplay.
'small' becomes 's' (abbreviation - e.g. clothes size).
'firm' becomes 'co' (a firm is a company).
'review' indicates anagramming the letters.
'by' says to put letters next to each other.
'liberal' becomes 'l' (abbreviation).
'under' is an anagram of 'undre'.
's'+'co'+'undre'+'l'='SCOUNDREL'
(Other definitions for scoundrel that I've seen before include "Cad" , "Red consul may be a rogue" , "Bounder" , "Hound" , "bad egg" .)