Mean 50s lout shut away (8)
I believe the answer is:
closeted
'shut away' is the definition.
(I've seen this before)
'mean 50s lout' is the wordplay.
'mean' becomes 'close' (I've seen this before).
'50s lout' becomes 'ted' (I am not sure about this - if you are sure you should give a lot more credence to this answer).
'close'+'ted'='CLOSETED'
Can you help me to learn more?
(Other definitions for closeted that I've seen before include "Cedes lot, being shut away" , "Do select, being in state of cautious privacy" , "Shut away for private talk" , "Do select (anag.)" , "Shut in small room" .)