Heartlessly cheap fellow! (4)
I believe the answer is:
chap
'fellow' is the definition.
(both can mean a man)
'heartlessly cheap' is the wordplay.
'heartlessly' says to hollow out the word (remove centre letters).
'cheap' with its centre taken out is 'CHAP'.
(Other definitions for chap that I've seen before include "(Of skin) become sore" , "Bloke, fellow" , "Man; (of skin) turn sore" , "Man, boy, fellow" , "cove" .)