Outlaw prohibited object, by the sound of it (6)
I believe the answer is:
bandit
'outlaw prohibited object' is the definition.
'bandit' can be an answer for 'outlaw' (I've seen this in another clue). I'm unsure of the 'prohibited object' bit.
'by the sound of it' is the wordplay.
'by' says to put letters next to each other.
'the sound of' becomes 'band' (I can't explain this - if you can you should give a lot more credence to this answer).
'band' next to 'it' is 'BANDIT'.
Can you help me to learn more?
(Other definitions for bandit that I've seen before include "Marauder" , "Member of a gang of robbers" , "Desperado" , "hood" , "Outlawed robber" .)