Being heartless, get away with trick (4)
I believe the answer is:
scam
'trick' is the definition.
(I've seen this in other clues)
'being heartless get away' is the wordplay.
'being heartless' means to remove the middle letters.
'get away' becomes 'scram' (I've seen this before).
'scram' with its middle removed is 'SCAM'.
'with' acts as a link.
(Other definitions for scam that I've seen before include "Swindle, fraud (colloq.)" , "Fraudulent scheme, swindle" , "Rip-off" , "Racket" , "Swindle (sl.)" .)