Bloke is vulgar, heartless (4)
I believe the answer is:
chap
'bloke' is the definition.
(thesaurus)
'vulgar heartless' is the wordplay.
'vulgar' becomes 'cheap' ('cheap' can be a synonym of 'vulgar').
'heartless' suggests removing the centre.
'cheap' with its middle removed is 'CHAP'.
'is' is the link.
(Other definitions for chap that I've seen before include "Man, boy, fellow" , "(Of skin) become sore" , "Bloke, fellow" , "Become sore; fellow" , "Fellow < makes > crack" .)