Wrongly instruct girl in class, we hear (9)

I believe the answer is:

misinform

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'girl in class we hear' is the definition.
I can't tell whether this defines the answer.

'wrongly instruct' is the wordplay.
'wrongly' becomes 'mis' (I can't justify this - if you can you should believe this answer much more).
'instruct' becomes 'inform'.
'mis'+'inform'='MISINFORM'

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(Other definitions for misinform that I've seen before include "Instruct wrongly" , "teach badly" , "Deceive" , "Wrongly advise" , "Wrongly teach" .)

I've seen this clue in The Irish News.

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