One saying nothing about parking charge (6)
I believe the answer is:
impute
'charge' is the definition.
(I know that charge is a more specific form of the action impute)
'one saying nothing about parking' is the wordplay.
'one' becomes 'i' (Roman numeral).
'saying nothing' becomes 'mute' (I've seen this in other clues).
'about' means one lot of letters goes inside another.
'parking' becomes 'p' (abbreviation on road signs).
'mute' placed around 'p' is 'mpute'.
'i'+'mpute'='IMPUTE'
(Other definitions for impute that I've seen before include "Attribute or ascribe - say fault" , "Attribute or credit to" , "Attribute (something bad) to someone" , "reckon" , "Ascribe, assign" .)