Lives heartlessly by deception (4)
I believe the answer is:
lies
'deception' is the definition.
(I know this)
'lives heartlessly' is the wordplay.
'heartlessly' suggests removing the centre.
'lives' with its centre taken out is 'LIES'.
'by' is the link.
(Other definitions for lies that I've seen before include "Deceits; is" , "Tall stories" , "pork pies" , "Reclines" , "Fabrications" .)