Remove sin from learner Seneca corrupted (7)
I believe the answer is:
cleanse
'remove sin from' is the definition.
'learner seneca corrupted' is the wordplay.
'learner' becomes 'l'.
'corrupted' indicates anagramming the letters.
'l'+'seneca'='lseneca'
'lseneca' with letters rearranged gives 'CLEANSE'.
(Other definitions for cleanse that I've seen before include "absolve from sin" , "give absolution" , "Free of sin" , "purify from sin" , "Bathe" .)