Last words inscribed in the heart and the body (6)
I believe the answer is:
corpse
'the body' is the definition.
(a corpse is a dead body)
'last words inscribed in the heart' is the wordplay.
'last words' becomes 'PS' (last words in a letter).
'inscribed in' means one lot of letters goes inside another.
'the heart' becomes 'core' ('core' can be a synonym of 'heart').
'ps' going within 'core' is 'CORPSE'.
'and' acts as a link.
(Other definitions for corpse that I've seen before include "Roof beam" , "Dead body" , "Dead bodies" , "Cadaver, dead person" .)