Corrupt European is after X-rated lick (10)
I believe the answer is:
adulterate
'corrupt' is the definition.
(I've seen this in another clue)
'european is after x-rated lick' is the wordplay.
'european' becomes 'E' (abbreviation e.g. EU).
'is after' is a charade indicator (letters next to each other).
'x-rated' becomes 'adult' (I've seen this in another clue).
'lick' becomes 'rate' (both can mean speed).
'e' after 'adult' is 'adulte'.
'adulte'+'rate'='ADULTERATE'
(Other definitions for adulterate that I've seen before include "Make impure by addition" , "Mix with a poorer substance" , "Doctor" , "Debase by mixing with something inferior" , "Make poorer by adding another substance" .)