Uncomplicated foreign article on PM is backed (6)
I believe the answer is:
simple
'uncomplicated' is the definition.
('simple' can be a synonym of 'uncomplicated')
'foreign article on pm is backed' is the wordplay.
'foreign article' becomes 'le'.
'on' is a charade indicator (letters next to each other).
'backed' says the letters should be written backwards.
'pm'+'is'='pmis'
'pmis' back-to-front is 'simp'.
'le' put after 'simp' is 'SIMPLE'.
(Other definitions for simple that I've seen before include "Easily understood" , "Easy; herb" , "Naive" , "Plain and uncomplicated" , "A piece of cake" .)