Falsehood from cleaner fool (7)
I believe the answer is:
charlie
'fool' is the definition.
(I've seen this before)
'falsehood from cleaner' is the wordplay.
I cannot really understand how this works, but
'falsehood' could be 'lie' (lie is a kind of falsehood) and 'lie' is found within the answer.
'cleaner' could be 'char' (char can mean a cleaner) and 'char' is found within the answer.
No letters remain.
This explanation may well be incorrect...
Can you help me to learn more?
(Other definitions for charlie that I've seen before include "Fool; man's name" , "Cocaine (colloq.), fool (colloq.)" , "succeeds. Bravo!" , "Personification of cocaine?" , "-- Chaplin" .)