Lass with car moving little devils (7)
I believe the answer is:
rascals
'little devils' is the definition.
(I've seen this in another clue)
'lass with car moving' is the wordplay.
'with' means one lot of letters go next to another.
'moving' indicates anagramming the letters (letters are moved around).
'lass' put after 'car' is 'carlass'.
'carlass' anagrammed gives 'RASCALS'.
(Other definitions for rascals that I've seen before include "monkeys" , "Knaves" , "Mischievous children" , "Scoundrels or naughty children" , "naughty boys?" .)