Struggles with moral weaknesses, losing heart (4)
I believe the answer is:
vies
'struggles' is the definition.
(I've seen this in other clues)
'moral weaknesses losing heart' is the wordplay.
'moral weaknesses' becomes 'vices' (I've seen this before).
'losing heart' suggests removing the centre.
'vices' with its middle removed is 'VIES'.
'with' acts as a link.
(Other definitions for vies that I've seen before include "Contends" , "Struggles" , "Competes, carries on rivalry" , "Strives with, rivals" .)