Banter in bar getting really heartless, sadly (8)
I believe the answer is:
raillery
'banter' is the definition.
('raillery' can be a synonym of 'banter')
'bar getting really heartless sadly' is the wordplay.
'bar' becomes 'rail' (rail is a kind of bar**).
'getting' says to put letters next to each other.
'heartless' suggests removing the centre.
'sadly' indicates an anagram.
'really' with its centre taken out is 'rely'.
'rely' with letters rearranged gives 'lery'.
'rail'+'lery'='RAILLERY'
'in' is the link.
(Other definitions for raillery that I've seen before include "Banter, back-chat" , "Satirical banter" , "Good-humoured teasing" , "(Example of) banter" , "Light teasing repartee" .)