Artless member trapped in web of lies (6)
I believe the answer is:
Here is my best explanation:
'artless' is the definition.
('simple' can be similar in meaning to 'artless')
'member trapped in web of lies' is the wordplay.
'member' becomes 'mp'.
'trapped in' is an insertion indicator.
'web of lies' becomes 'sile' (I can't justify this - if you can you should give a lot more credence to this answer).
'mp' inserted within 'sile' is 'SIMPLE'.
(Other definitions for simple that I've seen before include "A piece of cake", "Not complex, complicated or involved", "Straightforward, not elaborate", "Easily understood", "Uncomplicated; herb", "Easily done/understood", "The opposite of difficult or elaborate", "Easy; herb", "Plant with medicinal properties" and "Plain or easy".)