Latest heartless conclusion? (4)
I believe the answer is:
last
'conclusion?' is the definition.
(I know that conclusion can be written as last)
'latest heartless' is the wordplay.
'heartless' means to remove the middle letters.
'latest' with its middle taken out is 'LAST'.
(Other definitions for last that I've seen before include "model for a leprechaun" , "Final; keep going" , "model of repair" , "Hold out" , "Latest" .)