Magic vehicle carrying Santa to France with bit of help (7,2,4)
I believe the answer is:
sleight of hand
'magic' is the definition.
(sleight of hand is a kind of magic)
'vehicle carrying santa to france with bit of help' is the wordplay.
'vehicle carrying santa' becomes 'sleigh' (vehicle used by Santa Claus).
'france' becomes 'f'.
'with' says to put letters next to each other.
'bit of help' becomes 'hand' (to give someone a hand is to give them help).
'sleigh'+'to'+'f'+'hand'='SLEIGHT-OF-HAND'
(Other definitions for sleight of hand that I've seen before include "Doctor or student doctor" , "Trickery" , "Prestidigitation" , "Legerdemain" , "Skilful deception" .)