Instruction in audit once misconstrued (9)
I believe the answer is:
education
'instruction' is the definition.
(I know that instruction can be written as education)
'audit once misconstrued' is the wordplay.
'misconstrued' indicates anagramming the letters.
'audit'+'once'='auditonce'
'auditonce' is an anagram of 'EDUCATION'.
'in' acts as a link.
(Other definitions for education that I've seen before include "Teaching - knowledge" , "Process of acquiring knowledge" , "studies" , "A tonic due (anag.)" , "Cautioned about learning process" .)