Expose fraudster, we hear, one in extreme position (7)
I believe the answer is:
outlier
'we hear one in extreme position' is the definition.
I can't tell whether this defines the answer.
'expose fraudster' is the wordplay.
'expose' becomes 'out' (to out someone is to expose them).
'fraudster' becomes 'lier' (I am not sure about this - if you are sure you should believe this answer much more).
'out'+'lier'='OUTLIER'
Can you help me to learn more?
(Other definitions for outlier that I've seen before include "Isolated data point" , "Something detached from the main grouping" , "Remote member of a group" , "Exception" , "Extreme deviation from the mean - our tile (anag)" .)