Less than perfect devious sons aren't commonly taken in (2,6)

'less than perfect' is the definition.
I don't know anything about this answer so I can't tell whether it can be defined by this definition.

'devious sons aren't commonly taken in' is the wordplay.
'devious' is an anagram indicator.
'aren't commonly' becomes 'ain't' (non-standard or 'common' way of saying 'aren't').
'taken in' means one lot of letters goes inside another.
'sons' with letters rearranged gives 'noss'.
'noss' going around 'aint' is 'NO SAINTS'.

Can you help me to learn more?