Cross, once raves about potential reformer (2-3)
I believe the answer is:
ex-con
'raves about potential reformer' is the definition.
I know nothing about this answer so I cannot judge whether this works.
'cross once' is the wordplay.
I cannot really understand how this works, but
'cross' could be 'x' (X is cross-shaped) and 'x' is found within the answer.
an anagram of 'once' is 'econ' which is located in the remaining letters.
This accounts for all the letters.
This may be the basis of the clue (or it may be nonsense).
Can you help me to learn more?
(Other definitions for ex-con that I've seen before include "Former jailbird" , "Former prisoner, in short" , "One who has served time" , "having defected from Tory party?" , "Old lag" .)