Heartbroken, a mourner clutches charm (7)
I believe the answer is:
enamour
'charm' is the definition.
('enamour' can be a synonym of 'charm')
'heartbroken a mourner clutches' is the wordplay.
'clutches' indicates the answer is hidden within the clue (I've seen 'clutching' mean this).
'ENAMOUR' is hidden within 'heartbroken a mourner'.
(Other definitions for enamour that I've seen before include "entrance" , "Inspire with love; charm" , "Enchant" , "Charm, captivate" , "Fill with love" .)