Last cut -- heart, again! (6)
I believe the answer is:
encore
'again' is the definition.
(thesaurus)
'last cut heart' is the wordplay.
'last' becomes 'end'.
'cut' means to remove the last letter.
'heart' becomes 'core' ('core' can be a synonym of 'heart'**).
'end' with its last letter taken off is 'en'.
'en'+'core'='ENCORE'
(Other definitions for encore that I've seen before include "Request to sing it again" , "Cry for repeat performance" , "Let's hear/see it again!" , "Additional work performed" , "Bonus" .)