I am to find lesson corrupt (7)
I believe the answer is:
immoral
'corrupt' is the definition.
(similar in meaning)
'i am to find lesson' is the wordplay.
'i am' becomes 'I'm' (contraction).
'to find' says to put letters next to each other.
'lesson' becomes 'moral' (as in the moral of the story).
'im'+'moral'='IMMORAL'
(Other definitions for immoral that I've seen before include "involved in depravity?" , "Violating accepted principles of right and wrong" , "Without values" , "Depraved" , "scruples" .)