Engaged in protecting cross, talisman against evil (6)
I believe the answer is:
amulet
'talisman against evil' is the definition.
I can't judge whether this defines the answer.
'engaged in protecting cross' is the wordplay.
'engaged in' becomes 'at' (to be 'at' a task is to be engaged in doing it).
'protecting' indicates putting letters inside (inserted letters are held or protected).
'cross' becomes 'mule' (a mule is a cross of a donkey and a horse).
'at' enclosing 'mule' is 'AMULET'.
Can you help me to learn more?
(Other definitions for amulet that I've seen before include "Small charm" , "Charm, lucky token" , "Charm worn against bad luck" , "A type of lucky charm" , "Charm worn to ward off evil" .)