I'm taking the attitude it's a fraud (9)
I believe the answer is:
imposture
'a fraud' is the definition.
(I've seen this before)
'i'm taking the attitude' is the wordplay.
'taking' says to put letters next to each other.
'the attitude' becomes 'posture' (posture is a kind of attitude).
'im'+'posture'='IMPOSTURE'
'it's' acts as a link.
(Other definitions for imposture that I've seen before include "deception" , "Fraud" , "Trick" , "Pretending to be another person" , "Assumption of a false identity" .)