Doctor Freud takes in a detective and cons (8)

'cons' is the definition.
('defraud' can be a synonym of 'con')

'doctor freud takes in a detective' is the wordplay.
'doctor' indicates anagramming the letters.
'takes in' means one lot of letters goes inside another.
'detective' becomes 'ds' (detective sergeant).
'freud' with letters rearranged gives 'defru'.
'defru' placed around 'a' is 'defrau'.
'defrau'+'ds'='DEFRAUDS'

'and' is the link.