Rogue in swindle over parking (5)
I believe the answer is:
scamp
'rogue' is the definition.
(I've seen this in another clue)
'swindle over parking' is the wordplay.
'swindle' becomes 'scam' (scam is a kind of swindle).
'over' means one lot of letters go next to another (in a down clue, some letters go over others).
'parking' becomes 'p' (abbreviation on road signs).
'scam'+'p'='SCAMP'
'in' acts as a link.
(Other definitions for scamp that I've seen before include "Scallywag" , "Little Devil" , "A young rascal misbehaving in camps" , "Troublemaker" , "Impish youngster" .)