Expressionless girl embraced by heartless bloke (6)
I believe the answer is:
glassy
'expressionless' is the definition.
(thesaurus)
'girl embraced by heartless bloke' is the wordplay.
'girl' becomes 'lass' (lass is a kind of girl**).
'embraced by' is an insertion indicator.
'heartless' means to remove the middle letters.
'bloke' becomes 'guy' (I've seen this before).
'guy' with its middle taken out is 'gy'.
'lass' going inside 'gy' is 'GLASSY'.
(Other definitions for glassy that I've seen before include "Describes eyes lacking liveliness" , "Vitreous, like expressionless eyes" , "Reflective" , "vacant sort of look?" , "Describes eyes which lack liveliness" .)