Clean something counterfeit with brief expression of contempt (7)
I believe the answer is:
shampoo
'clean' is the definition.
(to shampoo your hair is to clean it)
'counterfeit with brief expression of contempt' is the wordplay.
'counterfeit' becomes 'sham' (sham is a kind of counterfeit).
'with' is a charade indicator (letters next to each other).
'brief' means to remove the last letter (a shorter or briefer version of the word).
'expression of contempt' becomes 'pooh' (I've seen this before).
'pooh' with its final letter taken off is 'poo'.
'sham'+'poo'='SHAMPOO'
'something' acts as a link.
I am not very happy about this link. It may be part of another bit of the clue.
Can you help me to learn more?
(Other definitions for shampoo that I've seen before include "Washer for locks" , "cleansing liquid" , "Cleansing agent" , "Hotel freebie - Warren Beatty movie" , "Would Mao shop for this cleaner?" .)