Talk with heartless person disobeying rules (4)
I believe the answer is:
chat
'talk' is the definition.
(thesaurus)
'heartless person disobeying rules' is the wordplay.
'heartless' says to hollow out the word (remove centre letters).
'person disobeying rules' becomes 'cheat'.
'cheat' with its centre removed is 'CHAT'.
'with' acts as a link.
(Other definitions for chat that I've seen before include "An inconsequential and informal talk" , "tittle-tattle" , "Small songbird of the thrush family" , "waffle?" , "Have friendly informal conversation" .)