Mother returned by 1 without thinking what might be wrong (8)

'1 without thinking what might be wrong' is the definition.
I can't tell whether this defines the answer.

'mother returned by' is the wordplay.
'mother' becomes 'ma' (ma can mean mother).
'returned' says the letters should be written in reverse.
'by' becomes 'orally' (I am not sure about this - if you are sure you should give a lot more credence to this answer).
'ma' reversed gives 'am'.
'am'+'orally'='AMORALLY'

Can you help me to learn more?