Rascals about to reach Germany on Sunday (4)
I believe the answer is:
cads
'rascals' is the definition.
(I've seen this in another clue)
'about to reach germany on sunday' is the wordplay.
'about' becomes 'ca' (short for circa).
'to reach' is a charade indicator (letters next to each other).
'germany' becomes 'd' (vehicle registration code for Deutschland).
'on' means one lot of letters go next to another.
'sunday' becomes 's'.
'ca'+'d'+'s'='CADS'
(Other definitions for cads that I've seen before include "'Blackguards, bounders (4)'" , "Knaves" , "Rotters" .)