Sham work without fee turned up (6)
I believe the answer is:
pseudo
'sham' is the definition.
(I know that sham can be written as pseudo)
'work without fee turned up' is the wordplay.
'work' becomes 'op' (common abbreviation for 'opus').
'without' means one lot of letters goes inside another ('without' can be similar in meaning to 'outside').
'fee' becomes 'dues' (I can't justify this - if you can you should give a lot more credence to this answer).
'turned up' is a reversal indicator.
'op' enclosing 'dues' is 'oduesp'.
'oduesp' written backwards gives 'PSEUDO'.
Can you help me to learn more?
(Other definitions for pseudo that I've seen before include "Pretentious, insincere" , "Fake, mock, false" , "Use pod (anag.)" , "Prefix meaning false; o dupes!" , "Pod use is fake" .)